Where to buy Bathrooms Stuffs in UK?

Depends what you mean by 'stuffs'

Do you mean the actual bath, toilet etc?

Plumbing?

Toilet roll?

Shower gel?

A hardware store?

Department stores are the norm.

Never heard of 'bathroom stuffs' if you mean bathrooms then there are many places you can buy them for DIY, builders merchants to specialist bathroom shops in the high st, if you mean fixtures and fitting then you can purchase them at the same places you get the bathrooms from and also many supermarkets too, if you mean shampoo, cleaners, soaps etc then anywhere you get your groceries from and there are also some high street stores which sell just those along with any chemist

I heard that their toilets flush backwards, is that true? Asking for a friend..

What 'stuffs'?

You need to be more specific.

You could mean anything from a a bottle of shampoo to a bath-tub.

https://www.victorianplumbing.co.uk/?gclid=EAIaIQo...

Here's just one! If you Google you'll find quite a lot. Even BathroomsRUs!!

in the hardware if plumbing fittings