Right, had a look at the wiring....
4 parts!?!
1. The main connector with 6 wires:white, grey, black, blue, red and green (see attached pic)
2. Three thicker wires taped together (black, red and green) only the black wire was attached to the radio by a plastic plug thing and didnt seem to affect the radio's function when removed (earth??)
3. One thick black wire with a round connection (aerial??)
4. A black connector with 6 small circular holes, attached to 6 wires. NOT attached to the current radio
The attached pictures show the main connector and radio wires.
Any ideas on where to go from here would be very very much appreciated!
Thanks
Ben