Thanks. Been out shooting the real LSR (!) and only just seen your reply.
We modelled the team scores on a 1 point differential but it made the influence of the bonus points too great in comparison. As we were really keen to adopt the bonus point idea, as a leveller and also an encourager to the lower ranks, we had to find a way to make it work. Changing to two points per place position did the trick. The scoring scheme was presented at the AGM and there was a large majority vote in favour.