Of course they aren't quite that.
I hope you can see that the bulb is in a black softish plactic holder but it isn't the plug thing I have described above and I can't get them out.
It seems as though the knobs are glued on and I can't see how to get the controls apart so as to attack the bulbs from the front!
Now I don't believe all you ZX owners are driving around with blacked out heater controls - so whats the secret before I start sawing it up?
Interesting way it deals with photos! Perhaps I'll try again later!
jeremy