hi tony_m,
I used the BAL (WP1 I think it's called?) memberane tanking system. Very straight forward and it's sealed the room perfectly. I sealed the whole floor, and where the shower area is, from the pics you can see I tanked all the way up the wall but in all honesty, I don't think it was necessary to go so high. The water can't go above the height of the shower head.
The underfloor heating was the one from B&Q, simple to lay and works fine. I went for the adjustable thermostat in the end. Again, all very simple to fit. Any questions don't hesitate to ask.
Cheers