All the internals were very clean, no contamination of the electrics or motor, hence why I think it worth going down the gear replacement route. I have cancelled (I hope) my order for the brass gears having read comments about poor quality Chinese machining and have ordered these through Amazon:
Buy VDO Siemens 03G128063 4E0145950 059128063 059145950 Throttle Body Motor Repair Kit at Amazon UK. Free delivery on eligible orders.
www.amazon.co.uk
Hopefully a cut above the cheaper ones on eBay. We will see.
The original gears looked to have turned to mush but when removed and cleaned it was only the pinion gear that had really worn away.
I believe I was very lucky when the EML came on, I was stuck in heavy traffic for a long time, even justifying turning the engine off until the traffic moved. The next day I started the engine to see if my cheepo OBD App could reset the EML light (it did!) but when I stopped the engine there was a load clicking noise, which I latter concluded was the gears ratcheting. I guess It would fail in the open state but if not it could have been a breakdown call out.