Hopefully the job will be easier now.
If I get a couple of days to myself this week I'll swap my parts over and then we'll know for sure once and for all.
Ok, so I wasn't going to tackle this job till after my holiday, but now I have the info you very kindly supplied, I was itching to try it. I had a couple of hours free this morning, plus the sun came out, so I thought lets give it a go!
I now have a plaster on my thumb, and 3 little bits of black plastic that have come from places i cannot find, but the job is now done
Once I had removed the radio, I pulled the green collar back as far as it would go, but it was hitting the bulkhead, and needed pushing/wriggling to get it all the way out, and as you said, it is just being pushed in by pressure from the cable at the other end. Then I disconnected the temperature control cable, this was much easier having a spare unit in my hand, as you can then see where to push with a short screwdriver or similar to disconnect the clip that holds the white plastic cable guide. It was then easy to pull the end of the cable off, and the smaller wiring connector came off easily. Unfortunately the bigger electrical connector did not want to come out, and this turned out to be the hardest part. In the end I broke a bit off the connector on the end of the wiring loom, and lost some skin off my thumb, but it still would not come out. In the end I used brute force and a screwdriver as a lever to get it off. Reasembly was a doddle after that, and the electrical connector is so tight a fit that the missing/broken clip does not seem to matter, anyway it's all sorted now.
Any questions? please fell free to ask.