A couple of weeks back I got my first "Engine fault. Reduced power" error while pulling away vigorously at a robot.
Stopped and restarted the car and it was gone. For a while. However, this is now happening more frequently, when boosting from low rpm, so I took it in to Anton @ APS.
Scanned and found the code 30FE Overboost error. We cleared all errors and reset adaptation, and said I should come back after it has happened a few more times, so we can be sure of the error.
When I left I obviously wanted to reproduce limp mode, which happened, but now remains on even after taking the key out.
Will now take back tomorrow to have it looked at. Hopefully this is not expensive, but I am not overly optimistic.....