The solution

At first Barry assumed it was two separate pieces screwed together, with a compartment inside. Not a bad assumption, but a wrong one.

Barry trying to unscrew the two halves.

https://www.youtube.com/watch?v=oSeX7G9-2rU

Next he decided to clean the paint off to get a better look at it.

https://www.youtube.com/watch?v=LvpdQTcBmvE

Then he put it in a vice and gave it some hefty donks with a hammer.

This revealed the seam as the weld was put into shear.

And a little shelf on the end.

Chisel time!

Bingo!

All done!

https://www.youtube.com/watch?v=NaAjJRViw6k