Doors, locks, and a soon to be MOT

[MuffDaddy]

I have a 94 model, all is currently well except the doors won't unlock via the key. The battery has previously been flat. The key will turn and deactivate the immobiliser but not power the central locking. Is it simply a case of cleaning the switches in the cill to let the central locking know the doors are shut?

Also, I think I know the way in. In fact I definitely know a way in. Could someone PM me just in case I am missing something even more obvious.

[Pinx]

What do you mean by the way in ??