Hello again Tom,
Its probably worth mentioning that the custom order statuses I have configured, are visible under “Tools” > “Advanced Scripts”
I am by no means a programmer in any way and the snippet consists of bits and pieces I have found on stack overflow – so I am of course wondering whether it is my shabby code that is causing the problems.
However, I am able to select these custom statuses in the plugin rules, as you can see, so it seems it should be able to work.