Thanks for your comments. I do see where you are coming from suggesting it's foolish to get a plumber to do the tiling, however he advertised himself as a 'bathroom fitter and designer' with over 100 positive comments on check-a-trade and a 9.8/10 feedback rating.
Perhaps it's worth showing...
Steve, wish you lived close to me! As for not stepping in sooner, we had agreed £200 a day originally but at the end of the first week when he'd brought in two other guys and charged me £160 and £150 a day for them - I asked for a final bill to get the job finished because I was concerned about...