My last update. Everything's sorted now after a fair bit of toing and froing.
Much to my annoyance, it turns out my device was NOT a UK model - its Hungarian, and as a result the necessary hardware for Wallet to work isn't there. I was rather annoyed at that revelation because I'd given my IMEI several times for Samsung to check and I'd been told it was fine, it was their Technical Team who eventually contacted me by email that cleared it up. So with that I went back to where I purchased my phone... I'm not sure if I can say who, but they're named after the world's most famous rainforest. I'd had the phone for nearly 2 months by this point so I wasn't expecting any help but after I explained to them that it had taken this long to get an answer from Samsung and that the listing was misleading they agreed to a return and a full refund - shockingly good customer service I think, in all honesty I was bracing for a court case.
I still have an S22 Ultra - thank you very much Uswitch, Three and Samsung Holiday Cashback for getting me a flagship model for less than the current Google leading model or an iPhone14 😁
I hope this has been helpful and if you're having problems getting Wallet to work, make sure you verify the model is correct for your country - triple check.