Central Locking problem

Hi all, just joined for some really needed advice and info on the car... 2011, 1.2 tsi Fabia Elegance.

Problem is about the central locking BUT not the usual problems that I have read about.. Our problem only concerns the 'automatic central locking' once the car is in motion, typically 10 seconds after starting off the car used to then lock all doors & the centre console 'doors locked' button would be lit..

 Has anyone had this problem - if so what did you do to remedy it?so repeats every now and then the same clunk click sound coming from the doors. I figured it might be a sticky door lock mechanism - so copiously sprayed wd40 into all 5 locks. Initially no difference, then it worked fine, once. Now it's back to constantly trying to lock again...

I might add that the car does actually lock & unlock with the rc - perfectly normally, although the sound doesn't seem the same when it is locking (seems longer) but when I try all doors - they are locked. I recently changed the rc battery but this problem started a while ago before changing the battery...

Any ideas? Thanks!