Use an option "archive_author" to specify the author

lib/set-archive-author.php

@@ -1,6 +1,7 @@
 <?php
 
-// Set the post_author to be "2"
+// Find a username specified in the option "archive_author"
+// Set the post_author (in $data) to be the id corresponding to the user
 
 function set_archive_author($data, $postarr)
 {
@@ -10,7 +11,18 @@ function set_archive_author($data, $postarr)
 		return $data;
 	}
 
-	$data['post_author'] = 2;
+	$archive_username = get_option('archive_author');
+
+	if ( !empty($archive_author) ) {
+		if (is_int($archive_author)) {
+			$archive_author_id = $archive_author;
+		} else {
+			$archive_author_id = get_user_by('id', $archive_author);
+		}
+		if ( !empty($archive_author_id) ) {
+			$data['post_author'] = $archive_author_id;
+		}
+	}
 
 	return $data;
 }

templates/entry-meta.php

@@ -1,13 +1,12 @@
 <div class="govuk-body-s"><?php
 
-// If the post is owned by a deleted user, set it to the archive user
-$tmp_author_id = get_post_field('post_author', $post->ID);
-if ($tmp_author_id > 2) {
-	$tmp_user = get_user_by('id', $tmp_author_id);
-	if (empty($tmp_user->user_login)) {
-		error_log("post {$post->ID} has deleted user $tmp_author_id", 0);
-		add_filter('wp_insert_post_data', 'set_archive_author', '99', 2);
-		wp_update_post($post);
+// If the post is owned by a deleted user, patch it to the archive user
+$check_author_id = get_post_field('post_author', $post->ID);
+if ($check_author_id > 1) {
+	$check_user = get_user_by('id', $check_author_id);
+	if (empty($check_user->user_login)) {
+		error_log("author of post {$post->ID} is deleted user $check_author_id", 0);
+		add_filter('wp_insert_post_data', 'set_archive_author', 99, 2);
 	}
 }