There is a wiring harness that passes into the trunk lid at one of the hinges. That may be damaged. It happens.
I have a button by my left shin in my car. You are in England so maybe it's by your right shin?
Edit: I just realized that you can't really inspect that without opening the trunk.
All modern cars have some sort of internal trunk release so you can't lock someone in there. I'm pretty sure we have one. Crawl through your fold down seat and look for it. The handle glows in the dark (if it's "charged")
Last edited by WDE46; 01-31-2013 at 03:28 PM.