Just in case it helps anyone as I think it’s a common issue - I’ve just fixed the central locking button by the drivers inside door handle. Mine would lock but only unlock if I pressed it for about 10 seconds or so...
I removed the door card and then the switch from the inner door handle. It prises apart around the base, and has a clear rubber protector over the circuit board. The section of circuit board which sits under the unlock button had a small corrosion patch on it. I used a TINY bit of mothers/metal polish on a cotton bud to gently clean it up and cleaned off with electrical contact cleaner and it now works perfectly.
Didn’t take any pictures - but is very obvious when you prise the switch apart as to how the button completes the curcuit. The buttons push a circular bit of rubber down across the circuit board to complete the circuit and on mine it clearly wasn’t making good contact as a result of the corrosion (more of a black etching than powdery rubbish). My switch cover was in great condition whereas the ebay ones are all scuffed, so I initially just wanted to see if the cover comes off at the very least (which it does very easily) but the corrosion patch was easy to see and worth a go for a few minutes.
Hope it’s useful to someone...
