Door Lock Replacing

[Grey13]

Hi, has anyone replaced their main van door lock. My van is a Swift Accord 2010 and the lock looks like this. Any tips, any suggestions about where to buy etc.
Do I have to replace whole mechanism or can I just change barrel and keys?

http://www.qis-uk.co.uk/Pics/Door_Lock_Outside.JPG
http://www.qis-uk.co.uk/Pics/Door_Lock_Inside.JPG

Is this perhaps what I am looking for?
https://www.caravanaccessoryshop.co.uk/product/hartal-hsc-door-lock-for-swift-caravans-lh/3384

My one key does not unlock the door. Already had a new key cut after much pain finding out where to get it done but that is faulty, worn already.

 

[Raywood]

It is a long time now since we had the problem but the lock on our Eldiss failed while we were on site 400 miles from home. As speed was essential we went to the nearest dealer and bought the whole thing which meant it was quick and easy. Given the caravan is now insecure I would be tempted just to replace the lot as quickly as possible rather than delay particularly as your insurer might wonder about any delay if there is a theft.