I didn't go down to my sons place to use his charger because man flu got me. Anyway, I'd already sprayed the magsafe 2 plug with switch cleaner but wasn't game to spray the laptop end. Today I soaked cotton wool buds with switch cleaner and cleaned the socket laptop end and it seems to have done the trick. I've never heard of this before but fingers crossed, I've done it.
Well, a couple of weeks and a few charges later, it's still working perfectly. Whoda thought it. Hope this thread helps someone else out, and thanks again for the help.