I sent this a few hours ago to the list but it seems to have gone adrift ! - If it has appeared twice I do apologise.
Steve,
In support of what Hilary is saying, I've checked a couple of Juvenile models from the late 80's that I still have ! and these were fitted with Wolber 600 x 28A's (28-541) tyres on Superchromix 600A rims and utilise 65mm drop Weinmann alloy sidepulls & Weinmann (Junior) levers.
hope this helps.
Bob Reid
Stonehaven
Scotland