How do I bathroom / kitchen / extension? etc.

I’ve never managed to reply to my own messages. It seems the issue of waste pipes is diameter. Specifically finding something in 32mm apparently. I need to read up more but if anyone can suggest where specifically to read I’d be v grateful! It seems confusing to me that the standard for waste pipes and the standard for traps/sink wastes are different… according to my plumber

Original:

I have an unexpectedly urgent rush to do a downstairs loo :/ help!

1) high level toilets - is there any substantive difference between Burlington (£434 ex seat), Canterbury (£329), Hudson Reed (£271), Windows (£339), etc. I’m inclined towards Burlington because I know they’re good, and maybe not worth saving £100 on.

2) copper basin wastes. I have an old fashioned janitor’s sink - like this
but bronze not chrome. The plumber says drain pipes are normally UPVC, but is there any disadvantage to buying a (wildly overpriced) copper p trap and having copper pipe showing until it disappears into boxing?

Thank you!