Sliding door lock

Has anyone ever taken the sliding door catch/lock to pieces? Mine won't actually lock either with the key or from inside, though from outside with the key it feels and sounds like it should be locking....
The lock is the not-in-the-handle type, if it makes any difference

 

I havent, but i had the same issues when i got the bus, i sent mine to swampys old school lock shop and he sorted all my locks and cut me new keys.
I think it was about a tenner to get the sliding door lock barrel fixed.

 

I'll have a quick look inside when it's not so cold my fingers won't work but thanks for the tip!

 

Late style slider??