Do you just need the barrell and key? If so I have a set that I can send you.Agree. The Givi top boxes are easy to break in to.
I have one here somewhere that came with a bike I bought years ago. I lost the keys, probably during a house move, and a couple of years ago wondered what was rattling around inside. I was in in seconds. It's easy to replace the lock, but costs over £60 for a new one, so it'll remain in the loft.