If you are replacing it then chances are the replacement will need the pipes altered anyway, and tiling will be easier with the valves out the way completely.
If it were mine I would drain it down, chop the pipes a couple of inches above floor level, remove the paint from the top inch or so of pipe (scraping/wire-wool) and stick a push-on stop end on each pipe.
Electrically, if you are not completely sure which circuit it is on, turn the whole consumer unit off before you disconnect the cable from the flex outlet plate.