Hello,
Sorry, it took me so long to get around to sorting the conflicting plugin but I have been away with work.
I did as you instructed, and after turning them all off etc I was able to determine the conflicting plugin is Advanced Gutenberg blocks. Once I switched this plugin off everything works fine. I am happy to drop the Advanced Gutenberg plugin off the site permanently as I wasn’t really using any blocks from it anyway.
So I suppose that means you don’t need to do anything.
Cheers Walking Rivers, Ivan