Aha! I'm beginning to see the problem.
What I'm looking for are lobster/crayfish pots - not traps. The traps are like dog kennels, while the pots are spherical.
I had, of course Googled the pots and came up empty in terms of ready made items - only dog kennels; so I decided as usual that I've got to make my own.
I've made a start in 0.5 mm brass rod, but it's such diabolical stuff to work with - out of the pack. Then, as I said, it dawned on me (afterwards), that it should be annealed.
Overnight (instead of sleeping), I thought that I may as well just use copper wire. It's soft, and it solders easily.
So today I'll have a crack at the copper wire - unless someone knows of a manufacturer who makes O scale pots.
Thanks for everyone's interest.