Did the same today m8,unfortunately it's a dismantle(beyond repair)job.The lock is made of plastic and metal.Firstly remove the plastic shield around the central lock motor(cut,rip),remove the c/l motor(1 x 8mm nut),then dismantle the lock with a screwdriver and brute force,breakaway plastic and dig around.The problem appears to be the lock release "dangler"(top l/h corner) jamming in the mechanism.Getting a replacement lock 2 morro £15 (2nd hand),best option I reckon...
dalek, January 2006