Dipping my toe in the whole eBay auction shenanigans - and I managed to get what I think is a good deal. I won the following item for just £2 plus postage...
It's a die cast Crescent 5.5 gun (No. 1251), which I believe may be roughly compatible with 1/32 figures (?). While being a modern artillery piece (based on the WW2 British 5.5 inch gun) I have bought it as a bit of a poor man's Britain's 4.7 inch gun. It is designed to fire projectiles and is - according to the eBay description - in working order.
Now Crescent was a British manufacturer that shut shop in 1980, although I can't seem to remember them from when I was a kid (Corgi, Dinky and Britains were the ones I can recall). But they seem to be fairly well sought after on eBay so I was glad to grab this one at such a reasonable price.
As for use, I intend to 'Victorianize' it by adding a (removable) shield and some period looking wheel covers (like those on the Britain's 4.7). Nothing irreparable, all of which I could remove to get it back to it's original configuration should I want to. Painting is another thing - do I or don't I?
Hopefully it will look OK with my AIP Egyptians.
Link: Crescent die cast guns, tanks & trucks at Planet Die Cast