I mounted them the same way I've seen others mount them:
I'll concede that the design of the shoulder anchorage / guide I'm using isn't ideal (and for the record the bolt is only a temporary test bolt), so I'll flip the anchorage / guide on the belt, and then add some extra material to the roll cage mount. That *should* sort the problem... I hope.
The picture was taken on my phone, hence the low quality.