Update No.5: I've got my GTi back. 9 days at the dealer, a new ECU and apparently a number of referrals to the UK tech team and it's seems the end of a saga. I'm a placid person but this was beginning to test my patience. You just don't expect a 16 month old car with 16k on the clock to be off the road. I'm hoping its a blip. I must admit to having a smile on my face for the short drive home from the dealer. I'm planning on keeping it for another 18 months or so and if it behaves I may then go for an R. If it lets me down again VW may be losing a customer !