On the Rover 75's I've had, look at what's listed for Fuse 2
The "older" models with the full sized fuses gives 30A Fuse 2 as Traction Control
The "new" models with the micro fuses gives 30A Traction Control as Fuse 47.
Not sure if the MG's shared the fuse board but it would seem daft if they didn't.
Hope that helps, not confuse the issue.
Andy.
Fuse 2 is the green one in the bottom left hand corner (No. 1 is the yellow 20A one)