Post Box Lock

[joec1985]

If you have any pics from the vendor, showing the inside, or the door open, that may show if it can be cut.

 

[JohnD]

Thanks

So it is made of sections bolted together.

If any of the bolts are accessible, for example on the back, you could perhaps undo them and get access to the inside.

I can't make out the lock bolting arrangement clearly, but if there is a gap (without an overlap) between door and frame that you can slide a knife blade into, a padsaw or a slitting blade in a grinder would cut the bolt of the lock.

BS locks have anti-cutting features but if it is an inexpensive cabinet lock it won't have.

 

[Harry Bloomfield]

I suggest that you wait for the new lock and keys to arrive, try the new key in the old lock and, if it doesn't work, post pictures of the new lock and a new key here. It will be easier to work out how to open it when we know exactly which type of lock and key it is.

Long shot - ask your postie if he/she has any keys you could to try.