diff --git a/lib/mail/notify/delivery_method.rb b/lib/mail/notify/delivery_method.rb
index ab4079f..deaa6c9 100644
--- a/lib/mail/notify/delivery_method.rb
+++ b/lib/mail/notify/delivery_method.rb
@@ -6,20 +6,28 @@ class DeliveryMethod
       attr_accessor :settings, :response
 
       def initialize(settings)
-        raise ArgumentError, "You must specify an API key" if settings[:api_key].blank?
+        raise ArgumentError, "You must specify an Notify API key" if settings[:api_key].blank?
 
         @settings = settings
       end
 
-      def deliver!(mail)
-        @mail = mail
-        @personalisation = Personalisation.new(mail)
-        send_email
+      def deliver!(message)
+        params = {
+          template_id: message.template_id,
+          email_address: message.to.first,
+          personalisation: message.personalisation,
+          email_reply_to_id: message.reply_to_id,
+          reference: message.reference
+        }
+
+        client.send_email(params.compact)
       end
 
-      def preview(mail)
-        personalisation = Personalisation.new(mail).to_h
-        template_id = mail[:template_id].to_s
+      def preview(message)
+        template_id = message.template_id
+        personalisation = message.personalisation
+
+        Rails.logger.info("Getting Notify preview for template id #{template_id}")
         client.generate_template_preview(template_id, personalisation: personalisation)
       end
 
@@ -28,24 +36,6 @@ def preview(mail)
       def client
         @client ||= Notifications::Client.new(@settings[:api_key], @settings[:base_url])
       end
-
-      def email_params
-        {
-          email_address: @mail.to.first,
-          template_id: @mail[:template_id].to_s,
-          personalisation: @personalisation.to_h,
-          email_reply_to_id: optional_param(:reply_to_id),
-          reference: optional_param(:reference)
-        }
-      end
-
-      def optional_param(name)
-        @mail[name].presence&.to_s
-      end
-
-      def send_email
-        @response = client.send_email(email_params.compact)
-      end
     end
   end
 end
diff --git a/mail-notify.gemspec b/mail-notify.gemspec
index f901429..3652cc5 100644
--- a/mail-notify.gemspec
+++ b/mail-notify.gemspec
@@ -34,7 +34,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "rspec-rails", "~> 5.1"
   spec.add_development_dependency "standard", "~> 1"
   spec.add_development_dependency "sqlite3", "~> 1.6.2"
-  spec.add_development_dependency "webmock", "~> 3.16.0"
   spec.add_development_dependency "rspec-mocks", "~> 3.12.6"
 
   spec.add_dependency "rack", ">= 2.1.4.1"
diff --git a/spec/mail/notify/delivery_method_spec.rb b/spec/mail/notify/delivery_method_spec.rb
index aab5fe5..5a64507 100644
--- a/spec/mail/notify/delivery_method_spec.rb
+++ b/spec/mail/notify/delivery_method_spec.rb
@@ -1,165 +1,256 @@
 # frozen_string_literal: true
 
 require "spec_helper"
+require "mailers/test_mailer"
 
 RSpec.describe Mail::Notify::DeliveryMethod do
-  before do
-    ActionMailer::Base.add_delivery_method(:notify, Mail::Notify::DeliveryMethod)
-    ActionMailer::Base.delivery_method = :notify
-    ActionMailer::Base.notify_settings = {
-      api_key: api_key
-    }
+  let(:mock_notifications_client) do
+    notifications_client = double(Notifications::Client)
+    allow(notifications_client).to receive(:send_email)
+    allow(notifications_client).to receive(:generate_template_preview)
+    allow(Notifications::Client).to receive(:new).and_return(notifications_client)
+    notifications_client
   end
 
   let(:api_key) do
     "staging-e1f4c969-b675-4a0d-a14d-623e7c2d3fd8-24fea27b-824e-4259-b5ce-1badafe98150"
   end
-  let(:notify) { double(:notify) }
-  let(:preview) { double(Notifications::Client::TemplatePreview) }
-  let(:mailer) { TestMailer.my_mail }
-  let(:personalisation) { {} }
-  let(:request_body) do
-    {
-      email_address: "myemail@gmail.com",
-      template_id: "template-id",
-      personalisation: personalisation
-    }
-  end
-
-  let!(:stub) do
-    stub_request(:post, "https://api.notifications.service.gov.uk/v2/notifications/email")
-      .with(body: request_body)
-      .to_return(body: {
-        id: "aceed36e-6aee-494c-a09f-88b68904bad6"
-      }.to_json)
-  end
-
-  context "when API key is blank" do
-    let(:api_key) { "" }
 
-    it "raises an error" do
-      expect { mailer.deliver! }.to raise_error(
-        ArgumentError,
-        "You must specify an API key"
-      )
-    end
+  before do
+    ActionMailer::Base.add_delivery_method(:notify, Mail::Notify::DeliveryMethod)
+    ActionMailer::Base.delivery_method = :notify
+    ActionMailer::Base.notify_settings = {
+      api_key: api_key
+    }
   end
 
-  context "with a view" do
-    let(:personalisation) do
-      {
-        body: "# bar\r\n\r\nBar baz",
-        subject: "Hello there!"
-      }
+  describe "settings" do
+    let(:notify) { double(:notify) }
+    let(:preview) { double(Notifications::Client::TemplatePreview) }
+    let(:message) do
+      TestMailer.with(
+        template_id: "test-id",
+        to: "test.name@email.co.uk"
+      ).test_template_mail
     end
 
-    it "has access to the settings" do
-      expect(mailer.delivery_method.settings[:api_key]).to eq(api_key)
-    end
+    it "provides the API key when one is set" do
+      mock_notifications_client
+      settings = {api_key: api_key}
 
-    it "calls Notify's send_email service with the correct details " do
-      mailer.deliver!
+      delivery_method = described_class.new(settings)
+      delivery_method.deliver!(message)
 
-      expect(stub).to have_been_requested
+      expect(Notifications::Client).to have_received(:new).with(api_key, nil)
     end
 
-    it "gives access to the response" do
-      mailer.deliver!
+    it "raises an error when the API key is not set" do
+      mock_notifications_client
+      settings = {api_key: nil}
 
-      expect(mailer.delivery_method.response.id).to eq(
-        "aceed36e-6aee-494c-a09f-88b68904bad6"
-      )
+      expect { described_class.new(settings) }
+        .to raise_error ArgumentError, "You must specify an Notify API key"
     end
 
-    it "shows a preview" do
-      preview_stub = stub_request(:post, "https://api.notifications.service.gov.uk/v2/template/template-id/preview")
-        .to_return(status: 200, body: {}.to_json)
+    it "provides the base url when one is set" do
+      mock_notifications_client
+      base_url = "example.com"
+      settings = {api_key: api_key, base_url: base_url}
 
-      mailer.preview
+      delivery_method = described_class.new(settings)
+      delivery_method.deliver!(message)
 
-      expect(preview_stub).to have_been_requested
+      expect(Notifications::Client).to have_received(:new).with(api_key, base_url)
     end
   end
 
-  context "with a template" do
-    let(:personalisation) do
-      {
-        foo: "bar"
-      }
-    end
-    let(:mailer) { TestMailer.my_other_mail }
-
-    it "has access to the settings" do
-      expect(mailer.delivery_method.settings[:api_key]).to eq(api_key)
+  context "with a template email" do
+    context "without any personalisation" do
+      let(:message) do
+        TestMailer.with(
+          template_id: "test-id-without-personalisation",
+          to: "test.name@email.co.uk"
+        ).test_template_mail
+      end
+
+      describe "#deliver!" do
+        it "calls the Notifications API with the correct params" do
+          notifications_client = mock_notifications_client
+
+          message.delivery_method.deliver!(message)
+
+          expect(notifications_client).to have_received(:send_email).with(
+            template_id: "test-id-without-personalisation",
+            email_address: "test.name@email.co.uk",
+            personalisation: {}
+          )
+        end
+      end
+
+      describe "#preview" do
+        it "calls the Notifications API with the correct params" do
+          notifications_client = mock_notifications_client
+
+          message.delivery_method.preview(message)
+
+          expect(notifications_client).to have_received(:generate_template_preview).with(
+            "test-id-without-personalisation",
+            {personalisation: {}}
+          )
+        end
+      end
     end
 
-    it "calls Notify's send_email service with the correct details " do
-      mailer.deliver!
+    context "with personalisation" do
+      let(:message) {
+        TestMailer.with(
+          template_id: "test-id-with-personalisation",
+          to: "test.name@email.co.uk",
+          personalisation: {name: "Name", age: "25"}
+        ).test_template_mail
+      }
 
-      expect(stub).to have_been_requested
-    end
+      describe "#deliver!" do
+        it "calls the Notifications API with the correct params" do
+          notifications_client = mock_notifications_client
 
-    it "gives access to the response" do
-      mailer.deliver!
+          message.delivery_method.deliver!(message)
 
-      expect(mailer.delivery_method.response.id).to eq(
-        "aceed36e-6aee-494c-a09f-88b68904bad6"
-      )
-    end
+          expect(notifications_client).to have_received(:send_email).with(
+            template_id: "test-id-with-personalisation",
+            email_address: "test.name@email.co.uk",
+            personalisation: {age: "25", name: "Name"}
+          )
+        end
+      end
 
-    it "shows a preview" do
-      preview_stub = stub_request(:post, "https://api.notifications.service.gov.uk/v2/template/template-id/preview")
-        .to_return(status: 200, body: {}.to_json)
+      describe "#preiview" do
+        it "calls the Notifications API with the correct params" do
+          notifications_client = mock_notifications_client
 
-      mailer.preview
+          message.delivery_method.preview(message)
 
-      expect(preview_stub).to have_been_requested
+          expect(notifications_client).to have_received(:generate_template_preview).with(
+            "test-id-with-personalisation",
+            {personalisation: {age: "25", name: "Name"}}
+          )
+        end
+      end
     end
   end
 
-  context "with optional fields included" do
-    let(:mailer) { TestMailer.my_mail_optional_fields }
-    let(:request_body) do
-      hash_including(
-        email_reply_to_id: "custom-reply-to-id",
-        reference: "ABC123XYZ"
-      )
-    end
+  context "with a view email" do
+    let(:message) {
+      TestMailer.with(
+        template_id: "test-id-with-a-view",
+        to: "test.name@email.co.uk",
+        subject: "Another subject"
+      ).test_view_mail
+    }
 
-    it "calls Notify’s send_email service with the optional fields" do
-      mailer.deliver!
+    describe "#deliver!" do
+      it "calls the Notifications API with the correct params" do
+        notifications_client = mock_notifications_client
 
-      expect(stub).to have_been_requested
-    end
-  end
+        message.delivery_method.deliver!(message)
 
-  context "when a base url is specified" do
-    before do
-      ActionMailer::Base.notify_settings = {
-        api_key: api_key,
-        base_url: "http://example.com"
-      }
+        expect(notifications_client).to have_received(:send_email).with(
+          template_id: "test-id-with-a-view",
+          email_address: "test.name@email.co.uk",
+          personalisation: {subject: "Another subject", body: "This is the body from the mailers view.\r\n"}
+        )
+      end
     end
 
-    let(:personalisation) do
-      {
-        body: "# bar\r\n\r\nBar baz",
-        subject: "Hello there!"
-      }
-    end
+    describe "#preview" do
+      it "calls the Notifications API with the correct params" do
+        notifications_client = mock_notifications_client
+
+        message.delivery_method.preview(message)
 
-    let!(:stub) do
-      stub_request(:post, "http://example.com/v2/notifications/email")
-        .with(body: request_body)
-        .to_return(body: {
-          id: "aceed36e-6aee-494c-a09f-88b68904bad6"
-        }.to_json)
+        expect(notifications_client).to have_received(:generate_template_preview).with(
+          "test-id-with-a-view",
+          {personalisation: {subject: "Another subject", body: "This is the body from the mailers view.\r\n"}}
+        )
+      end
     end
+  end
 
-    it "calls appends the new base url to the request" do
-      mailer.deliver!
+  describe "Notify optional fields" do
+    describe "email_reply_to_id" do
+      it "is present in the API call when set" do
+        message = TestMailer.with(
+          template_id: "test-id",
+          to: "test.name@email.co.uk",
+          reply_to_id: "test-reply-to-id"
+        ).test_template_mail
+
+        notifications_client = mock_notifications_client
+
+        message.delivery_method.deliver!(message)
+
+        expect(notifications_client).to have_received(:send_email).with(
+          template_id: "test-id",
+          email_address: "test.name@email.co.uk",
+          personalisation: {},
+          email_reply_to_id: "test-reply-to-id"
+        )
+      end
+
+      it "is not present in the call to the Notify API when not set" do
+        message = TestMailer.with(
+          template_id: "test-id",
+          to: "test.name@email.co.uk"
+        ).test_template_mail
+
+        notifications_client = mock_notifications_client
+
+        message.delivery_method.deliver!(message)
+
+        expect(notifications_client).to have_received(:send_email).with(
+          template_id: "test-id",
+          email_address: "test.name@email.co.uk",
+          personalisation: {}
+        )
+      end
+    end
 
-      expect(stub).to have_been_requested
+    describe "refence" do
+      it "is present in the API call when set" do
+        message = TestMailer.with(
+          template_id: "test-id",
+          to: "test.name@email.co.uk",
+          reference: "test-reference"
+        ).test_template_mail
+
+        notifications_client = mock_notifications_client
+
+        message.delivery_method.deliver!(message)
+
+        expect(notifications_client).to have_received(:send_email).with(
+          template_id: "test-id",
+          email_address: "test.name@email.co.uk",
+          personalisation: {},
+          reference: "test-reference"
+        )
+      end
+
+      it "is not present in the call to the Notify API when not set" do
+        message = TestMailer.with(
+          template_id: "test-id",
+          to: "test.name@email.co.uk"
+        ).test_template_mail
+
+        notifications_client = mock_notifications_client
+
+        message.delivery_method.deliver!(message)
+
+        expect(notifications_client).to have_received(:send_email).with(
+          template_id: "test-id",
+          email_address: "test.name@email.co.uk",
+          personalisation: {}
+        )
+      end
     end
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index af240cb..f4e353d 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -14,7 +14,6 @@
 require "action_controller"
 require "action_mailer"
 require "pry"
-require "webmock/rspec"
 
 require "mail/notify"