I don't know what a "52 plate" is, but I had this problem on a 1999 corsa. Replace the actuator on the boot lock. Look behind the panel inside the hatch. It should be a cigarette packet size unit with a linkage joining it to the lock. I got a replacement from a breakers yard for £5, but I chose it myself from a low milage car.
Jmmy, August 2008