So, set myself the task of getting the dashboard out today, should be easy given it only occupies half a dozen lines in the manual. Wrestled off the steering wheel (prior application of release spray then rocking it at various different opposing points did the trick) and got the steering clamp off before the serious business set in. The inner dash screws in the bobbins came out, the outers just spun the nuts behind the dash. after getting access to the nut, just about got it to undo, but it was a close run thing. And the genius work of the dual purpose courtesy switch and fascia mount defeated me - nut just spun round, and the front is circular... Had to cut it off, luckily there was just room.
Still got the n/s door switch bolt, and fascia screw to remove, but feels like progress. Lying in the footwell with my head under the dash and my feet on the bulkhead had all the same joy (ie none) of sorting the dashboard wiring of my Scimitar in the 90's - I was more flexible then though!
After I've done the dash I might have a go at removing the door, seeing as it's just a case of removing the split pin and sliding the outer tube down.
Given the split pin's not for shifting, looks like hacksaw work may be needed.
Looking for replacements for the multitasking courtesy switches, I see Banks have them at a shade under £15 each, but no stock. Looks like they are common to Austin A30/35s, as this seller's switches look very similar to me.
https://www.austina30a35parts.co.uk/product/all-electrical-parts/courtesy-light-switch-zswh001/ZSWH001