I'm pretty sure you'll be able to. I've not delved into the inside of the scooby door, but some other cars I've worked on have either a cage or locking plate behind the barrell. Sometimes you need a special tool to remove the plate so the barrell can be removed, other times, the plate can just be slid off to the side freeing up the lock.
If you have any trouble, give me a shout and I'll give you a hand. Just point out where Gemma has parked her car so I can put mine at a minimum safe distance.