My wife went out in our 98 300TDI this morning but when she tried to lock the doors she found the central locking not working, she then attempted to manually lock the doors with the key and found that the key just turned round and round in the lock, this happend after she manually unlocked the car when she went out.
I have issues with the electric windows ECU (I have tried soldering, and am now looking at purchasing a replacement as this has not worked).

Does the window ECU have any input into the Central Locking?
By the way the key fob itself is fine as we recently added new buttons and batterys.

the car is going in for a timing belt change next thursday and it is a mess at the moment with the glove box and 2 door panels removed. I would at least like to resolve the locking problems before it goes to the dealer, i would be too embarressed to send it in as it is!