A while ago Railway Magazine did a gauge survey of railways in Britain, in which they mentioned that St Michael's Mount Goods Funicular was 2ft 5 1/2 in gauge, which they said was unique in the UK and unusual even abroad. But isn't it roughly equivalent to 750mm gauge, fairly common on the Continent?
Within 0.7 of a millimetre!! It's also the represented gauge for HOe.
Paul