Leaving part P aside for the moment, there are reasons other than fickle political whim why you can't do it.
For a start, you are highly unlikely to find a neutral wire leading to a light switch. What you will most likely find is a flat twin and earth cable in which the black wire is switched live, not neutral. If you connect a socket across these two, nothing much will happen - until you try to use the socket. The light will come on and whatever you plugged in won't work properly.
Even if you follow that wire back to a its light fitting or junction box where there will be a real neutral, putting a socket on a lighting circuit is a bad idea because they are only rated at five amps - or six if you're lucky. Every time somebody tries to use that socket for something big, like a washing machine for example, the fuse in the consumer unit will blow and lots of lights will go out.
Your new socket should, like the other one, be spurred off a 30 amp circuit. If you can't figure out how to do this then take Breezer's advice and find somebody who can.