Right. Bear with me because I've got half a dozen cabinets that all need replacement locks. Hopefully the forum massive can recommend a firm or two that could help.
This green cabinet is the first one.
I've found this, which looks like it would be a good match. But it's over £30.
Ironmongery Direct have been good when I've used, not for a while now mind. Not the cheapest but good service and they don't sell rubbish, based on my experience anyway.
Those locks are so easy to break into you may as well go for the cheapest as they are only a deterent. If you need real security then a multipoint locking system would be needed along with a bit of beefing up and floor anchors.
Why are you fitting new locks? If it is to improve security fair enough, as those ones are going to be really basic. However, if it is just because the keys are missing, it might actualy be easier to leave the locks and just get new keys.