When a manager tells you there is no need for a union rep as it is only an informal meeting

Love it. Seriously if you work for an employer that provides services to the public you should consider https://join.unison.org.uk/ or try out the "union finder" search engine at https://worksmart.org.uk//

"How would your office look if your manager was a cat?"

I must admit that as a trade union steward for many years I have come across some very odd managers but...:)