In reply to Fraser:
We had ours done recently.
6mtr square room.
Old Bath, toilet and sink ripped out and all tiling removed, new toilet in a different place to original one, no bath but a large walk in shower in a different place to the old bath.
New sink and cabinet in same place as original one.
Boiler moved from bathroom to other side of the wall in to the spare room.
Re tile all walls and lino floor.
We got a few quotes.
Typically there are 4 price zones.
Zone 1, the Polish plumber why quoted me 2.5k.
Zone 2, independent kitchen and bathroom company quoted 4k with 100% payment on satisfactory completion.
Zone 3, B&B, Wiks type place quoted 5.5k
Zone 4, Dolphin quoted 8k.
We have seen similar price differences in the kitchen and bathroom price's in our old house and in our new one.
We went with the second zone in all cases.
The only problem we had was with the bathroom in our new house, everything was fine but the toilet would not clear without 2 or 3 flushes.
The guy came back and altered the waste pipe but it didn't help so he got the manufacturer involved but they couldn't come for a month.
He asked for payment which I refused based on the contract saying 100% satisfactory completion.
He was not happy and asked for a 90% payment with just £400 held back until the toilet was sorted but I pointed out the contract again.
Ultimately he bought a new toilet and installed it all the while complaining that it was costing him money but I stood firm, my contract was with him not the manufacturer.
Once it was sorted I paid in full.