WordPress Dashboard getting mangled when plugin activated

When the plugin is activated it seems to corrupt the layout of the WordPress dashboard. Usually I have a 4 column layout on the desktop – see photo for example
https://photos.app.goo.gl/WjaY9jYdMnBYHw6r7

Each column is the same width and items can be dragged between columns to reorder them.

However, when the Appointment Hour Booking App is activated, it changes the layout of the dashboard. Second image as an example
https://photos.app.goo.gl/oCWEPCYn29kwuEgAA

This image is zoomed out (slightly) so you can see more of the issue. As you can see the WordFence panel now takes up the entire width of the Dashboard, the panels below it have no gap between them (and cannot be dragged to move) whilst other panels only take up the first column and leave a large area of wasted space to their right.

I have disabled all plugins and found the Dashboard to display correctly. Re-activating each plugin in turn indicates that the issues lies with Appointment Hour Booking only. I.e. with no other plugins enabled as soon as Appointment Hour Booking is enabled, the Dashboard display goes awry.

I’ve tried this with both classic and direct methods and it is the same result.

Unfortunately, this is making the Dashboard hard to use for the admin of the site in question.

In case it helps, WordPress 5.6.2, Linux (lightspeed) server, PHP 7.4

Hope you can help?

Thanks.

The page I need help with: [log in to see the link]