A catch phrase needn't be a long or particularly pithy thing.
Charlie Brown's was "good grief..."
I used to have a couple in Blacknose. One was "give me strength..." another was "Gordon Bennet.." but I suspected that many wouldn't get the latter, it was a bit old.
I used to hear women say "I'll swing for him/her" which didn't mean anything fruity, just that someone had made you so angry you'd kill them (and then be hanged for it).
OK, catch phrases for Beau Peep: How about one of the tuaregs or Abdul using "By the Beard Of Jabul!!" to express anger, or some other odd Arab-sounding name.
Dennis could say: "who's Jabul"?
Beau: "his wife"