Hi there Paul thanks for your reply, I've been at 3 dealers and they have been no joy,I contacted Citroen UK and after 4 e-mails the only answer I got was 6564QK was the changer for my car but when I re-contacted the dealers the part no is a citroen part no but they have no information,another blank.I have a weird plastic bracket in the left hand side panel in the boot and a similar type plug for the changer but it has 18 pins as opposed to my existing changers plug which has 12 pins(8 are used)I contacted clarion but they have no idea which one citroen might have used and 6564QK does not ring any of their bells.I don't even know if the head unit is capable of operating a changer, all be it there appears to be wiring in the boot for one.As you can tell I am new to all this and you mention in your previous reply about getting info free from the citroen service box, could you enlighten me as where to find this and access it, as it might be a help. Thanks again. John.