Hi
I'm going to be thorough as possible when explain my problem, along with what I have to tried to resolve it (to no success).

The car is an A4 2002 1.9TDi 130bhp

The fault is this; when you unlock the car (via key fob or manually) the central locking system continuously cycles. It sounds like the doors unlocking and locking continuously, however the latches aren't actually moving. Also interior lights flash in sync with the locks along with hazard lights.
To cancel the fault, you pull the valet switch inside the drivers side door. This stops the fault, and you can lock the car again. When you open the car, the fault will start again. If you do not pull the valet switch and then lock the car, the alarm will sound within 15 minutes and the locks will cycle continuously every 30 or so seconds.
I cannot pinpoint anything happening to cause this fault, the alarm starting going off in the middle of the night etc and eventually we had the battery disconnected until we discovered the valet switch trick.
I removed fuse 24 (30a) which is Comfort Electrics, this allows you to unlock the front doors manually only and the fault does not occur.

What we have tried.
Initially replaced the alarm horn in the boot of the car thinking this was causing the fault.
We uncovered both electrical looms on the front doors and repaired any faulty or suspicious looking wires.
Had the passenger seat out and checked the ECU for water damage (completely dry)

Having put the car on VAGCOM several times since the fault began, there are no error codes showing, at least that are relevant. After getting a fault in the drivers door we checked the wiring loom to find the Earth badly damaged. We repaired the wire and are going to run VAGCOM again and see if the door fault remains. (To hopefully provide us the next step)

Things that have been suggested to me.
Replace the drivers door latch
Replace ECU
Replace CCM
Replace CLM

Any help would be massively appreciated, and I can provide more information if I have missed anything out, cheers!