While one should certainly investigate the easy and cheap OBD-II scanner responses, if this turns out to be a transmission/controller problem, you'll need to take it to someone with a Rover-specific diag computer.
The most common cause for the fault you have is electrical-related. It will be interesting to find out what the issue is here.
Yes, I am still alive, and still in the Rover parts business.
Text me for greatest likelihood of finding me.
Dominic Perodeau/Global British is a thieving bastard, do not send him money.