[Richard1973]

Thanks for your quick reply.
You have spurred me on and I think I have fixed it.
I have undone all of the loom tape on the loom I was supplied and determined that the bulk of the wires from the blue plug do go directly to the CD changer bar a couple of thin red and white with yellow flashes wires, that are joined in a bridging block and then go to a thick wire of the same colour that joins the main loom.

I went out to the car and found the same thick red, white and yellow flash wire and found that as part of previous bodging, it has a bullet connector on the end.

I made up a temporary bridging wire and plugged it all in and voila I have a CD player.

Just soldering the two thin wires together now and will then put them into a bullet and try it again before hopefully putting the car all back together again.