Thanks for the advice regarding reading fault codes - I'll look into that. In fact the car is now exported back to the UK so it will be going to Bell and Colvill from now on - but Louwman Exclusive have done a good job for me in the Netherlands.
Interesting thing is that I managed to turn off the engine warning light! After spending some days with the battery disconnected I reconnected and started the car no problem, except for the engine warning....so I pressed the OS button and on came the OS warning. Turned off the engine. restarted and hey-presto! No warning lights! A quick drive around and all is good in the world!!
All things considered I believe it's just the rubbish software (many reported issues on the forum) but it will be interesting to see what the dealer has to say when they plug in the magic machine!
