You can always have the top retrimmed. Shouldnt cost much. I have got 2 for mine, one in black and yellow and the other in yellow and black!
Try these guys. They are from the company (Callow and Maddox) that used to make all the interiors for MG-rover (as well as a few other companies like Mercedes, Jaguar, Land Rover), but went bust as the work dried up when MG-Rover went under. One of the guys was (is) a member from here, Neo.
Rob - the Rover Coupe armrest is the only one that will fit the ZR mk1. It is important that you buy the actual plastic armrest from a 96-99 coupe as the plastic is black to match the upper part of your console. The 92-96 coupes had ash grey arm rest. The black leather top was only made between 92-96. So you have to mix and match. Very easy to swap. Make sure you get the 'coupe' handbrake bracket (this will support the armrest) and all the bolts. Hope this helps.