I guess it's one of those cultural differences between here in the U.S. and the U.K>, but, if it's available, why don't you consider a tile transition from floor to wall? This is a tile made to the same dimensions as the wall tile, yet with a radius at the bottom that smoothly transitions the wall tile to the floor. It's easily sealed and grouted and then makes the entire floor waterproof in case of spills or the tub running over. In fact, a tile or matching marble door threshold can be installed to keep
all spilled water in the bathroom.
The transition tile installation can seen if you'll scroll all the way to the bottom of
this
Best of luck!