Walk around in a black suit, white shirt, a black tie and a bowler hat, A Tweed blazer with corduroy trousers may work if you can't find a black suit. Wear a monocle instead of glasses, and don't smoke anything less than a hamlet cigar (or maybe a smoking pipe). Grow a pointy moustache for that special touch. I'd say carry a rifle to put those blasted delinquents in their place, but that might get you arrested... but you can substitute the rifle for a walking cane and tap them tap their head and say "I say, old chap... what on earth do you think you're doing? "
You'll be her hero for sure.