Free Traffic Legal Advice

It was my understanding conditional and absolute discharges followed findings of guilt but did not constitute criminal convictions per se thus did not need to be disclosed as such (my main aim).

An absolute discharge is still a conviction. It is, however, immediately spent so would not need disclosure when the rehabilitation act applies.

A conditional discharge is spent when the period of the order expires.

The SJPN does not have a specific page titled IDPC

It wouldn't have. It is a term used in Criminal Procedure Rules and not many people would know what it means.

I did note when stating my driving license number there is administrative error whereby my Car registration is listed instead, and is listed as 'foreign DL' although I have a full UK license - I presume a small clerical error as such however would not amount to defence.

Correct

I was advised by one solicitor that my options would be to Plead not guilty and check the evidence which carries no guarantees, although case can be won if the evidence is incorrect.

You already have the evidence. The police need to show that:

- It was your vehicle involved (they have photographs of it)
- You were driving (they have your response to the "request for driver's details")
- The vehicle exceeded the speed limit (they have evidence from the device).

Unless you object to any of the evidence they have provided the statements you have copies of will be provided to the court and accepted as true and accurate. If you believe they do not have evidence to prove those three elements you need to say so. You will need to have the writer of those statements appear in court (or via video link) where they can be questioned (cross examined). Just wanting them to slip up or make a procedural error really won't cut it. 

I was advised there may be practical problems when prosecuting lower priority cases with Evidence often missing/incomplete and many cases resolved before court.

There seems nothing missing. There is no reason for the police or CPS to seek a resolution before court. This is not a parking ticket or a railway fare evasion (where there are opportunities o do that).

If all the evidence ‘checks out’, consider offering a guilty plea to a lower speed (e.g. 90mph) (apparently this depends upon the prosecutor in court and whether they’re willing to accept the reduced speed,

Why should the prosecutor do that? There is evidence of your speed provided by an approved device. All you have is a desire to see the penalty lessened. 

....but in his experience, most are, as it brings the case to an end quickly and with minimum cost/effort and is then more likely the magistrates will impose a conditional discharge (due to the lower speed).

I would be interested in his experiences. I have never, ever seen or heard of a Conditional Discharge being imposed for a straightforward speeding offence. Whilst it is in the court's power to do that, there is no provision for it in Magistrates' Sentencing Guidelines. A lower speed results in a lower fine, that's all. There would be no problem securing your conviction at the alleged speed and there is no reason whatsoever for the prosecution to entertain a lower one. More than that, by your solicitor's reasoning, all a a driver has to do is simply agree to plead guilty to a lower speed and be subject only to a conditional discharge rather than a fine. That is absolute nonsense.

It was my understanding conditional and absolute discharges followed findings of guilt but did not constitute criminal convictions per se thus did not need to be disclosed as such (my main aim).

Already explained by me and others - a discharge (either absolute or conditional) follows a criminal conviction, so will not help. In any case, there is no reason whatsoever for a court to impose a discharge simply because you offer to plead guilty to a slightly lower speed. This solicitor is either deliberately misleading you or is unfamiliar with the sentencing of speeding offences. In either event I recommend you do not pay him or her any money for advice or representation. 

I do realise I am in an unenviable position...

I think your expectations are unrealistic. You are clearly not going to avoid prosecution in court. That process has already begun and it will not be discontinued, particularly on any of the bases you have put forward. With that in mind, you seem to have no realistic defence to the charge. Instead you are depending on an administrative or procedural error being made which is serious enough to see the prosecution fail. You have been served with the evidence the police will rely on to convict you and there is little or no scope for any issues with disclosure. If you want anything else from the police you will have to ask the court to order it. You will have to explain what it is and how you believe it either assists your defence or undermines the prosecution. Yes, errors are occasionally made and most of them can be rectified in court. Depending on one being made that will prove fatal to the prosecution is not really a very good idea.

You are really overthinking this. It really is a very minor offence, a conviction in a criminal court yes, but not one anyone is ever going to have any issue with.

I absolutely agree. I really don' know what it is you believe a speeding conviction will jeopardise.

I absolutely agree. I really don' know what it is you believe a speeding conviction will jeopardise.

Some driving jobs could be problematic. Though I doubt that is what is feared since it's the conviction rather than the points that is OP's worry.

I don't know how many times you need people to give you the same answer before it sinks in.

That pistonheads thread is nonsense, and 22 years old.

You have again referenced putting the prosecution to proof. This has already been answered.

It is a speeding conviction. Stop fussing FFS. And I say this as someone who undergoes SC checks routinely and has previously been convicted of motoring offences in court.

You have been getting some rather odd legal advice, a conditional discharge is unheard of in a speeding prosecution, put that out of your mind. I get the impression that you have got yourself far too worked up over this minor matter. Speeding offences are all about the numbers, had you been doing 95mph you would have been offered a fixed penalty, but at 96mph the case goes to court, this is at the discretion of the police, forces may vary slightly but they are all very rigid with their policies, I suspect to avoid rather pointless discussions. Magistrates are very likely to stick to their guidelines which are for 4 to 6 points for 91 to 100 in a 70 limit, you are therefore likely to get 5 points and a fine equivalent to one week's net income less a 33% discount for a guilty plea. There is no reason at all for the prosecution to accept a lower speed when they have a good measurement from HADECs, they may do so in different circumstances such as a police follow check, but not when they have a good reading.
Pleading not guilty in the hope that the prosecution make some error is clutching at a very small and flimsy straw covered with grease, as mentioned it will cost you considerable additional prosecution costs when you are found guilty, but it will put things off for a while, but you will have to appear in court eventually. Courts are not terribly impressed by defendants who plead not guilty without a viable defence.
Getting a minor motoring conviction is not the end of the world, even when a job involves driving, the condition is most often "not exceeding 6 points" and I would be amazed if it ever stopped you getting a visa, what concerns the authorities are offences of dishonesty, and drug offences, not traffic offences.