UK Auto Repair Questions?
Thank you for your question and sorry for the delay, my name is Steve and I am a fully qualified vehicle technician with over thirty years in the trade, hopefully I can answer your question for you.
The problem with the Astra Twin Top is unfortunately quite common and is normally due to a failed wire in the boot mechanism. This is the wire that takes power between the body and boot which has a habit of breaking leaving the boot lock without power. This prevents the lock from operating and so the system will as you have mentioned block the roof.
Repair is difficult and it may be possible to operate the boot using tech II diagnostic equipment, once the boot is open the faulty wire should be repairable.
I am sorry to not be able to give an easier solution to your problem.
But I hope this answers your question but do please feel free to ask any further details by replying to this thread.If this does answer your question please click accept and rate me, this allows me to continue. Even After clicking accept you can continue to ask further questions on the matter by replying to this thread.Many ThanksSteve