Thanks!
Thanks to all who contributed to this. I've always thought it funny that we Brits are so schizophrenic about our measurements - beer in pints, wine in 75cls, whisky in drams, etc. The thought of a plus 40 thou rebore on an 84mm barrel, and so on. . . .
Anyway, the cause of all this is now past, and was completely irrelevant when the time came. I was trying to get a hire van, and only one smaller than a Luton or a 1.5-ton (tonne?) thing with a tail-lift was available in the time required - a small Transit Connect. Anyhow, I had worked out, thanks to Tony, that I could just get a Vin in there, so turned up to collect it, only to find that the previous hirer had just wrapped it round a tree!
Fortunately for me, the very-nice-man-in-the-office was so embarrassed about this that he'd rung a neighbouring branch and found a vast VW that could've taken half-a-dozen (sorry - 6) Vins at once. (No, I don't know why it wasn't available before, either - but he let me have it at the same price as the much smaller thing, so I didn't wait around to find out) So I set off into the sunset and all's fine now. Had to have a 0.473176-litre or two on getting home, though, after tacking round the M25 all day . . .
TTFN
Jeremy