Boot lock won't open

[cindy]

I have a 2007 Zafira B 1.8 Petrol. I have a problem with the boot not opening, have changed both the lock and button and had the electric checked, there is electric going through to the boot button fine the lock just won't open.

Anyone have any ideas please. 

[Vauxhall Owners Club]

are you able to dismantle the boot interior to gain access to the latch mechanism and then release it from there?
Once you have released the boot then it would be wise to replace the latch mechanism which may be the faulty component