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Thanks for your help, I phoned a few local dealers. For anyone looking to this as a reference:
You have to visit the dealer with the log book, a photocard driving licence and bank / credit card. They will then order the key from Germany. The key comes pre-cut within 5 days. You then need to take the car into the dealer who will reprogramme the new key, your existing key and the car to a new code, thus isolating the lost key. Average dealer price is �155.
Moral of the story - don't lose your keys I suppose!