Anti burst locks

[EddieB]

I wonder if someone could help? Recently my drivers side lock has become impossible to keep locked. It shuts and the key turns fine ( I replaced the barrel about a year ago) but when you lock the door and try to remove the key, turning the key from 3pm to 6pm, it unlocks the door. For a while I could very delicately remove the key to keep it locked but nolonger. Similarly if I lock the door from the inside and then rattle the handle outside, it unlocks itself. I've done a temporary fix with an iternal spring to keep the internal lock indicator pointing upwards, but have to push the catch down from the inside to get out the vehicle and yesterday locked myself out the van with the engine running when I got out to check my parking! I'd like to avoid buying a whole new lock if possible. I've heard that there are internal springs in the lock that can wear - might one need replacing and if so, which one, where do you get them and how do you go about replacing? I've checked the spring (without taking the lock apart) you can view from the outside and it doesn't appear appear to be broken but is a little corroded. I've researched online but can't see this particular problem mentioned. Thanks for your help.

[Neil Bymouth]

Is thete a local locksmith that might be able to help?