1993 XJ-S radio fitting/fixings

I have had a 1993 XJ-S 4.0 conv. since new. The radio has always been stupidly insensitive and I feel like getting round to investigating it (there's probably a trimmer round the back)but can anyone tell me how to get the thing out of the dash? Do I need to remove the heater console or do I need some shims down the side of the radio?? Thanks Martin