My Mrs used the XKR yesterday and reclined the seat a bit. I got in afterwards and it won't sit back up - I can hear the motor but there's no movement. Like the dimwit I am, I reclined it a bit further to test the mechanism (???) and it still won't sit back up. I'm now having to drive in a near horizontal position.

 

I had the same problem with my passenger seat. It's probably an open circuit in the seat control module board right along the edge. Try swapping the modules and see if you can get the seat to return to your favored position. There are two nuts holding holding the module in which you can access by raising the seat.
I found a replacement on ebay for$80, and if do a search of the forum you will find some procedures for repair, but it is a delicate soldering job.