i have taken a photo of the fuse, but do not know how to get it into my album
I think it is likely that something like the wiring for the lighting could be the cause.
I have a Mira Elite 2 electric shower, that was installed before I purchased the house some 3 years ago here in Ireland (same reg's as UK) just recently after someone came in and did some work on lights in the kitchen, which were connected to lights in the bedroom, the electrical shower cord...