It's the brackets rather than the flaps that get trashed on a 110 though, so some new brackets tucked up further are a must to avoid trashing the bodywork when the bracket gets torn off. I too have seen people that tie them up out of the way with bungees or whatever, to avoid the classic "reverse over a grass bog and rip the flap off" problem!
I like the hinge pin idea though, I might work on that
Tim is yours a 90 or a 110 though? mudflaps are further forwards on a 110, not on the crossmember like a 90.