The warmer environment still did not help. I felt I was in danger of shattering the transparent plastic lamp holder. Instead I removed the opaque plastic surround which seems more robust and is held in by robust plastic ratchet mouldings. Once out I could see why the transparent lampholder was reluctant to budge except at the steering wheel end. It was held in by a robust metal spring. I could depress this easily with the surrounding mount out and everything disconnected. Then putting in the new led bulb was easy but of course I reverse polarised it on the first attempt.
All fine now, but I still wish there was a suitable moulding on the left hand side and wiring provision.
When all the main lights are led, it seems inconsistent of VW to leave tungsten filament bulbs in the boot and the front cubbyhole.