Limp Mode on startup

I'm having a limp mode problem when starting the car, which normally only happens after a long drive. Now my car is 1.9TDi Leon Stylance so this is not connected to the FR limp mode problem, as my car has never gone into limp mode while driving once the problem was cleared or it started normally. Also I must note that I have never gotten any warning lights on the dash.

Now my Seat garage seem to be giving out mixed signals as to whether the car is logging faults, at first they said it wasn't, then it was, and now its not and never has So they cant pin point the problem.

They did plan to replace the whole turbo, but on advice from Seat HQ/UK replaced my ECU chip (the main chip) instead. Car was fine for about a week and now the problem is back and getting worse then ever. Going from say 1-3 times a month, to 8+ times already this week! I have also noticed overall responsiveness of the car has dropping slightly. Which also happened a week before the ECU chip was replaced where the car was constantly unresponsive to a much greater extent then now, but I feel the car will end up in the same state soon.

I was also advised by Seat to try and let the car have a cool down period before switching off. As they were suspicious that the turbo was not being cooled enough and the ECU chip puts itself into limp mode before all the electronics switch off (as they remain on apparently for a minute or 2 after the car is switched off). Then when I come back to the car and start it, its in limp mode, requiring a restart to clear it. Anyway letting the car cool down for a minute before switching off has had no affect what so ever.

Now the car is due in again next Monday. I'm looking for advice before Monday as to whether I have have any options and what to say. I guess you cant reject a 1 year old car? This problem only started after around the time of its first full service. I have also come close to having a crash several times because of this problem, where I have tried to accelerate at a round-about and on a slip road from a motorway service station and over taking a stopped bus only to move at what I can only describe as a snails pace and be faced with oncoming traffic, and not being able to move!!

Ok this limp mode on startup has been fixed for a couple of weeks now by my dealer. Yay! Fault was a dodgy cable from the sensor to the ECU. New cable was hardwired and not had a problem since.

Only downside is that dealer has caused damage to my car while trying to fix it (not impressed) damaged scuttle dish and scratched side wing