After looking into this a bit further it's something to do with the Bowden cable and latch not fully opening or locking. To check the latch I am not going to strip the bike down to get at it buried underneath the leg guard so for the moment I have just unhooked the Bowden cable and all is well with the lock. Have never used the left hand compartment for anything valuable anyway so it will not be locked. Tinkering with all the issues I have had recently sure has me knowing a lot more about the bike which I guess is a good thing.