Whilst getting in to the car after a quick trip to the local shop, the seat decided to power forwards in to its minimum position.
This pushed my knees in to the dash again.
I supose that if you work out what is happening fast enough you can tuck your legs out of the way to stop the compression, but before you have realised it isn’t going to stop, you are already compressed.
Pressing the Memory 1 button, restored the normal seat position.
It seems that it misreads the key and goes for some minimum position by default.