Thought I'd post some piccies as I was doing this job and someone asked how to do it the other day. Every little helps.
I would imagine this proceedure is then same for Mk1 Ph1/2 and for both climate control and heater dials but, please correct me if I am wrong.
Firstly, remove ashtray and unclip gear lever gator. You will need to undo the two torx screws shown at top of picture and push out clips (from behind) shown at bottom of picture. You can then simply pull the ashtray housing out;
Next, remove the radio/cd player and tray from their housing and undo the four torx screws that are shown in the picture (two revealed when the ashtray housing was removed and two revealed when the radio/cd player was removed). The housing can then be pulled forwards, down and out;
Lastly, there are two bolts on the underside of the climate control unit that need to be undone. I used a 9/32 socket to undo these. Once they are removed the climate control unit can be pulled down and out allowing you to unplug;
Just remember to catch and screws or bolts that you remove so as they do not fall into the centre console abyss. That'll mean having to take the car apart further to retrieve the screws/bolts.
Hope this may be of help to someone. Thought I'd post it as the last owner of my car had obviously tried to lever the unit out, hence why I need a new one.