So after about 2 months of my pbd not working, like several other people on here, it has started operating again. It now opens and closes from the key, the boot button and the dash button. I cannot really attribute it to anything in particular although the car is being used more than it had been for the last year. It's probably doing about 100 miles a week now rather than 30 in lock-down (lots of very short journeys).
When it was not working I tried disconnecting the battery, I tried the hairdryer trick and even took the motor unit out " tapped" it and put it back in but none of these things worked. I was not able to use a techsteam on it but my OBD2 showed no fault. I had charged the battery a few times and bought a multimeter which showed it was in good condition.
Thank you for all the suggestions and help from everyone, in particular Herbie and good luck to the others who still have issue. Maybe they just need to be driven more but who knows why?