mk4 polo locks knackered

so my polos locks seem to be dieing one by one... first the drivers side (and central locking), then the boot so i'm worried that if the passengers side is going to die and i'm stuck!

Started taking it apart on the weekend and it seems the lock is working, turning the switch inside it and triggering some kinda switch inside (can here it click) The pin works to lock and unlock (i assume thats mechanical) and the locking from the key works (again i assume thats mechanical) but the unlocking doesn't....

Does that suggest the mechanism is broken or should i be looking at the pneumatic pump??

also - is there some cunning way of opening the boot from the inside?? going to be kind hard to get into that otherwise!

Cheers

sam