Hi Macc If you're going to take a peek at the wiring just a tip. When they were assembled at he factory, the looms were put into the cars and any unused plug connectors were usually wrapped in foam and then pushed through holes in the bulkhead to put them out of the way for the next stage of assembly. What you will be looking for (assuming that it has never been touched since the factory) is a fairly thick (about 12 wires +-) going off the main loom into a bulkhead gap if you pull that out of the gap, remove the foam you should have a multi-pin plug connector (can't remember the colour) it may well be even marked with a white factory label saying CD Changer. If you've got that you're in business. Your car being a Sovereign, I'd be very surprised if it hasn't got it. From the description of your mounting cage, you are sorted on that score. If you give me 20 minutes or so I will PM you on what parts are needed and prices. Bezza