Interesting and possibly useful for me too in the near future - I've had limp mode show up with the PRNDS lit up once in a blue moon, but - subjectively - it seems to happen a bit more frequently now.
It came on this morning, following a reverse off the drive, and stayed in limp mode as I drove off, but then disappeared and was ok when I turned the ignition off and then on again.
I could blame Neil, as he was the last person to drive it

, but that would be deeply, deeply unfair, as he's also managed to improve the trip average consumption more than I'd thought possible!