Converting 'Views Row Insert' (invalid style plugin)

Hi all,

I'm trying to insert blank rows into a view (so the the last row of my flexbox can be left-justified)... to achieve this attempted to port the 'Views Row Insert' D7 module. Installation works fine, but I can't enable it... when I try to enable it in a new view I get an " invalid style plugin" error... it is shown as a format option for an existing view, but whenever I attempt to enable it, nothing happens.

When I do these errors are in the logs: _views_create_handler - loading handler style failed: class views_row_insert_plugin_style_custom_row could not be loaded. Verify that the class has been declared and the class file has been registered in a hook_autoload_info() implementation. and Call to a member function uses_fields() on null in ViewsUiBaseViewsWizard->build_form_style() (line 341 of C:\wamp64\www\mattjaggar\web\core\modules\views_ui\wizards\views_ui_base_views_wizard.php).

views_row_insert.info used to contain the line:

files[] = views_row_insert_plugin_style_custom_row.inc

but I have already removed this and instead inserted the following to the end of views_row_insert.module as advised by https://docs.backdropcms.org/converting-modules-from-drupal

 function hook_autoload_info() {
   return array(
     'views_row_insert_plugin_style_custom_row' => 'views_row_insert_plugin_style_custom_row.inc',
   );
 }

When I run update.php I get the following warnings:

• Warning: include_once(XXXXXX/modules/views_row_insert/templates/views_row_insert.views.inc): failed to open stream: No such file or directory in include_once() (line 574 of XXXXXXX\core\includes\theme.inc).
• Warning: include_once(): Failed opening 'XXXXXXX/modules/views_row_insert/templates/views_row_insert.views.inc' for inclusion (include_path='.;C:\php\pear') in include_once() (line 574 of XXXXXXX\core\includes\theme.inc).

What I have tried:

1. Uninstalling and reinstalling the module
2. Running update.php and clearing the cache
3. Replacing all the references to drupal_xxx to backdrop_xxx
4. Placing a copy of 'views_row_insert.views.inc' in '/modules/views_row_insert/templates/' which didn't previously exist
5. Putting the hook_autoload_info() function at the top of the .module file instead of the bottom

I've rejigged lots of superficial things but the outcome is the same... can anybody help?

Many thanks!