Thank you for the further details.
(NIP's need to arrive within 14 days - unless there is a business owner of the vehicle etc.)
I think it very unfortunate that you were arrested. Of course once arrested they will secure your belongings and so that left you without your computer to help express your points about the case/s.
IMHO and personal opinion, (I am not a lawyer and cannot advise you), any speeding infringement that happens at the same 'time', same 'day', within the same stretch of road, cannot be taken as two offences. (I have not got a reference for this at the moment - may have time to find one later).
The Court is unlikely to take kindly to you quoting other cases where Police have been acquitted in part or whole, as each case stands on an individual basis. But perhaps that is for our info than the Court.
It does seem that it has all rather got out of hand.
Your going abroad when there was a hearing was perhaps not the best move? Or did you have representation.
On that aspect, you can provide the Court with an Advocate who can speak on your behalf, although I cannot recall if you need to be there but that is likely to depend entirely on what the Court is planning to do on that date. The Court Clerk will be able to advise you of this.
You say there are numerous emails, but not of that content. You must always ensure that all correspondence is not 'damaging' your case (that you are not 'hanging yourself').
Courts also do not like lengthy cases although they will recognise that it can happen 'with the best will on all sides'. Some solicitors might have simplified (to the Court) your case a while back, and I would urge you to seek legal advice (& as others have) as there are obviously a number of involved points to consider which is the best legal path for you to follow now.
Perhaps the Court failed to appreciate the legal aspects of your case. If the Court clerk badly advises then this will influence the Magistrates decisions.
Doing an Internet search on the case type is likely to have you locate the cases that you seek. (I haven't time now to do this or I would.)