Can anyone give me an idea of how much it would cost to refit a bathroom?

[VisitTheInfidelWithExplanatory]

It's very small (240cm x 137cm) and it needs completely gutting and redoing. I'm thinking new suite and fitting including electric shower or pump for mains shower) and tiles and tiling the floor around the bath up to the ceiling and maybe half way up the other walls.
I am totally clueless about this sort of thing so I could really do with a ballpark figure so I don't get taken advantage of!
tia :)

we paid £4k parts and labour for following:
-remove existing tiles and replaster

• fit new suite plus cabinet units
• fit new shower unit and bath and sink taps
• fit new shower screen
• tile floor and walls
• fit blind, toilet roll holder new light fitting
• wire in and fit towel heater

We bought all materials and fittings ourselves for £1.5k then paid £2.5k in labour.

it's much cheaper if you do the design and product sourcing yourself.