Having bought a replacement disc changer thinking the issue lay with the changer itself I then thought that I possibly ought to check if there was a live coming to the plug from the car and then no power coming to the socket....

Other than pulling the head unit out and the trim to check the cable isnt compromised at some point is there anythin obvious anyone can suggest?

Is there an earth being run down the cable? Is the connected? I wonder if maybe the CD changer cable has been disconnected from the back of the HU.

The CD changer is a blue connector behind the headunit, chances are if there has been an aftermarket headunit in the car at some point then it may have been left out.

If yours is an estate check the wiring harness under the cd changer as it is likely to be corroded (Rear washer pipe leaking)

Right got the head unit out and the green and blue socket isnt connected! However im not even sure if its the correct one, can anyone confirm?? Its not as wide as the connector in the back on the head unit??

Yes it is the correct 1.

There should be a yellow square plug on the end.

This does not do anything unless you want to run a sub.

Ah ok cool, I guess as the car had a sub and amp in it at some point the wiring for the yellow plug has been mangled!

THanks for the confirmation

check that all that wiring behind the stereo isn't an aftermarket harness - if youi take the glovebox out and have a dig you may find the original stereo wiring loom there!