remove shower from bedroom - URGENT

I've just pulled a shower ensuite out of a bedroom to convert it back into a proper bedroom. the shower is still connected to the wall at the moment as I'm trying to work out how to stop the plumbing behind the tap and completely shut it off to re-plaster the wall. Any one able to help? The tap is a mixer tap but has two pipes going to it. I guess hot and cold. I know I have to drain the system but then what do I do when I've pulled the thing off the wall? (this is the first time I've done any plumbing as I'm skint and can't afford to call a pro!)

either cap them off in the wall and plaster over them or if you can trace them back to a more convinient place do that and cap them off there making the piped in the wall dead.

i would try to trace back the pipes as far as possible and cap them off with decent soldered connections,easier if capped under floorboards due to access for any future problems/mods

You definitely do not want dead legs of pipe, as they'll either have static water or air in them. Even worse if they're inaccessible behind plaster!

dead legs should NOT be removed as you will deprive the bacteria,legionella and others of a place to breed.These are all forms of life and have rights too.
if u don't comply the ALF will dig up your dead mother ..