Re: changing a face plate
Unfortunately it isn't as easy as just changing the faceplate - For Sky+ you need two feeds from a satellite dish and the chances are that if your flat was built relatively recently (say in the last 5 -10 years) they may only have provided one feed from a shared dish. In order to get a second feed for Sky+ you will not only need a new faceplate but a second cable will need to be run from the communal system. Basically you will need to contact the management company who look after your block (and all of the communal equipment) but beware, it might not be cheap.
In the meantime it should be possible to continue to use Sky+ but you won't be able to record a program while you watch another.