Quick update in case its helpful to anyone in the future.
Covid made things a little different i think, there was no prosecutor to talk to however the legal advisor to the magistrates was helpful and happy to make the decision to do the deal, this took place in the courtroom, although i had spoken to someone (i think an advocate) half an hour before who had made them aware of what i was asking.
All was relatively pain free and ended up with a £3xx fine rather than the £8xx, and 3 points rather than 6.
Thanks for all your help MITM