I've no personal knowledge of the case, but I've watched the clip carefully, I know the road well and have the following points:
1) From the article: "The method of riding was considered so extreme by investigating officers from the Sussex Road Policing Unit that normal topping procedures were not considered appropriate. Instead, the rider was safely tracked using unmarked cars and an unmarked motorcycle in order to gather evidence to support a prosecution."
Unlike a car, the options for stopping a motorcycle are severely restricted in comparison. HOSTYDs (Hollow Spike Tyre Deflation Systems or "stingers") can't be used and "boxing in" tactics with such a small and quickly-accelerating vehicle are of no practical use.
2) "Also the Police made some dodgy manoeuvres to keep up with him. I think the Police were just as guilty of negligence letting him carry on for so long!"
What would you have had them do instead - ditch him? Driving a marked police vehicle at high speed in safety requires an extremely high level of training and skill, but to do the same in or on unmarked vehicles raises the bar even higher, as the "marked and visible" element disappears for other road users. Only the best of the best drive/ride such vehicles at high speed and this would have been a planned follow, not someone who "just happened" to be on patrol. The briefing for this type of operation would be comprehensive and - above all - would have concentrated on public safety.
Trained police drivers are exempt from the National Speed Limits in certain circumstances. This situation qualifies.
3) "Also in my opinion he must have been provoking the motorcyclist in front by being so close."
It would seem from the background of the case that this motorcyclist didn't need provoking at all - he was stupid and reckless enough all by himself.
4) "... he may have been driving dangerous, but at times he was only doing 30mph, they could have stopped him then."
You've clearly not tried it. Someone with high levels of adrenalin flowing would take scant notice of a marked car in those circumstances, let alone a plain one. The risk of him doing something even more reckless is then increased greatly. Officers know when and when not a stop will/will not have the greatest chance of success.
5) "Looking at it another way...if the police had received reports that he was consistently doing hugely excessive speeds then they need to gather the evidence. Pointless following him with blue lights flashing as he'd simply slow down. Equally pointless just doing him for, say, 45mph in a 30 limit...they wanted to remove him from the roads for a good period which makes sense IMO. And again no point in knocking on his door as there is no evidence that he was actually the person riding the bike."
Absolutely.
6) "I am quite sure if the Police had an easy option they would have taken it, as to identifying the rider although there is an obligation to give up the information regarding the rider it is always going to be open to abuse when the persons face isn't visible."
Correct, on both counts!
7) "It is up to the rider to prove that it is not him."
(2) Where the driver of a vehicle is alleged to be guilty of an offence to which this section applies—
(a) the person keeping the vehicle shall give such information as to the identity of the driver as he may be required to give by or on behalf of a chief officer of police, and
(b) any other person shall if required as stated above give any information which it is in his power to give and may lead to identification of the driver.
(3) Subject to the following provisions, a person who fails to comply with a requirement under subsection (2) above shall be guilty of an offence.
Penalty for failure to comply is 6 penalty points.
8 ) The commentary shows that the police rider was asked if he was "still comfortable" with the follow. This is standard practice and in the reply the rider states that the offending rider was "fast, but not very competent, especially bend assessment." This can be seen in the differing lines of approach taken on numerous occasions. It may be thought that an "incompetent" rider is easier to stop than a more competent one, but if the demonstrated behaviour is lacking, the risks increase.
About 2½ minutes into the video, the offending rider becomes aware of being followed. He then seems to turn the journey into a competition.
9) "Clearly the rider needed to be stopped before there was an RTA, but equally the 'boys in blue' needed the evidence to do so, which meant the unmarked police bike had to break regs as well. I'm glad in the end that he was stopped and that nobody got hurt."
I saw no clear opportunity for the (solo) police motorcyclist to stop the offending rider safely, with any real chance of success. "Road blocks" are prohibited tactics nowadays and - unlike the movies - people tend not to get up again after falling off at those sorts of speeds. He was arrested the following day, if dates from the article are to be believed. I would have thought that he would have been followed to conclusion of journey, then arrested once he'd dismounted - at least, that's what I'd have done.
Sorry for this lengthy post. I've tried to look at it from all sides, but this "summary" won't please everyone, of course.
Ray.