Hi and welcome to the forum, there are two types of plug fitted to the D5WZ heater the Beru GH001, 0100.228.340 this primarily fits the earlier MK2, it's cheapest from AVS car parts online. The later ceramic plug which is probably the one you need with the wires attached this is more expensive and are available on ebay from http://stores.ebay.co.uk/Diesel-Heaters-Spares?_rdc=1 http://stores.ebay.co.uk/Heater-Parts-Direct?_rdc=1 I don't have the part number for these but if you email either of these they will advise. Of course they are available from dealers for more dosh. Thanks, have phoned local Dealer and it would appear I have the later version of the heater according to them. I will order a VAG COM lead off ebay and see if just clearing any fault codes will work, I have to all too common problem of the car not heating up/varying coolant temp, and SWMBO is giving me grief that the car isn't warming up on her way to work.