Doubt it’s a kit – looks like an antique that’s been round the block a few times.   Not top quality machining, so perhaps made in a Victorian Brass Foundry in someone’s spare time using simple equipment.

Hard to date. Have a look at the screws – hand-made, inch-sized, and not Whitworth suggest early.

Dunno what to recommend – I like to retain the history, others might restore to ‘as new’.

Dave

Almost certainly unique – and unless there exist still drawings for the full-size version, perhaps even to the maker’s own design but based on contemporary practice.

If the screws are not Whitworth, what else might they be? Something “standard” only to the builder’s place of employement? Continental?

The feed-pump looks somehow not quite true to the rest of the engine, perhaps a replacement for the original: it seems a different alloy, and with slightly better machining though looking a bit unfinished. This could be contemporary with the replacement column.

I wonder if it once had railings right round it, the missing uprights having been replaced by those countersunk screws.

I’d agree with Charles – just give the old gal enough attention to let it amble round on a modest air supply. Keep the column and pump as they are, as part of the entire machine’s story.