Ruji your a star!

Just been out to try again and your right, the locking mechanism is in the top of the radio!
However, those slots are way too thin to let a release key through, so I took off the front of the radio, and the two pieces of metal that lock into the cage were held in by a washer that sits between the piece of metal and the locking strip....
Anyway, nudged them out with a screwdriver and out it came!
Fantastic!
No I just need to sort out this switched earth and a suitable HU!
Anyone know what type of CD changer lead this uses, as I believe there is more than one type? It's a round plug with a funny shaped connector, I can get a pic if that would help.
Cheers, Kae.