This is s lightly better than your other question. (No idea why you did two.)
What you have is a 'loop-in' circuit. Unless you understand what that is get an electrician before you have a fire or worse.
Second in the UK it is illegal for you you carry out that work in a bathroom if you are not a 'Competent Person' (Building Regs.) or you have to have it checked by a 'Competent Person'. Doing so can also affect your chances of selling your house and/or your house insurance.
t
January 2008