It isn't so much a case of strength, but the brake pipe rubbing on the side panel as the suspension & steering moves.

I see you'r point, but wouldn't a rubber grommet suffice?

Hole is too small as it stands anyway.

TT

I was goona drill it out bigger, kinda glad i didn't now ;)

Yep that's the issue the flexy can rub against bodywork hole so mr via doesn't like it.