That's interesting, Graham. I have never heard that before. It makes sense, though. That gooey green jelly must have originated somewhere...
I did a little researching and found the real thing in Escoffier's Complete Guide to the Art of Modern Cookery, in case you're interested in making it, D.B.:
"Chop or cut into fine Julienne 50g (2 oz) mint leaves; place in a basin and add 25g (1oz) caster sugar, 1 1/2 dl (5 fl.oz.) vinegar, a pinch of salt and pepper and 4 tbsp. water; mix all the ingredients together."
I'm sure it would be just fine with red wine vinergar, Devil's Brew. Probably pretty nice!
"Knowledge is power. Arm yourself."