Side strap mount bracket issue

I have a 7D2 with a Vello grip. Using my Carry Speed strap and attaching the metal bracket to the tripod mount on the bottom of the grip, after a while the bracket will start to move around as the bolt starts to loosen. I don't want to tighten the mounting bolt too tight as it might damage the grip.

Is there any way of attacking the bracket so it won't start turning?

Thanks