I've found on the internet that they say it's common for the wires on the passenger side to corrode but I've checked both sides and they're fine.

With the driver side disconnected the car locks on the passenger side and stays locked as it should, I believe the problem to be on the driver side for this reason.

The part on the pillar that the latch catches had a black piece of rubbery plastic around it, it's quite badly damaged so have now removed it, this qouldn't affect anything would it?