I've had no more problems with locking/unlocking so maybe this was a one off glitch. The alarm seems to be working ok but the red led is still on continuously. ( This is the red light in the middle of the rocker switch which dissables the internal motion sensor and the anti towaway function.) Normally this would flash momentarily when changing a function or flash continuously when the alarm is armed and doors locked. I've been advised the alarm backup battery may be faulty but I dont know where it is.
Any advice would be appreciated even if you dont have the complete answer.