I tend to favour the term "Savage Infants" personally, but "Tall Children" is a winner too, I shall remember that one.

"Try to act your age, not your shoe size" sometimes works when trying to restore order with a group of 25 rowdy teenagers (I'm a teacher).

Recently, however, the smart ones have been shouting back "British or European?"

Thanks for tall children...

European could either be French or Italian standard. Not sure if it's useful for a comeback though, since they are both in circa the same range.