Wondering if anyone might recognise what lock this fits?

Its a pretty large example, the curtains 48mm diameter at its widest, the bore is for a largish 1 gauge SWG pin key, and the barrel height is 17mm.

For some reason Chubb is stuck in my mind, but when I recall all the largish powder proof locks I've seen the curtains in them were small in comparison. This has a slight spiral on its circumference, the obvious radiused cut-out, plus the steel tooth riveted in place suggesting it's not only a curtain but presumably a bolt thrower actually engaging the bolt. Wish I had the rest of the lock to go with it, a complete mystery where it's from and where I got it!
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