Definitely nothing illegal about filming whilst driving although I fail to see what you would persecute the van driver for.

It's as bad as those ridulous cyclist videos where they put themselves in harms way seemingly on purpose then shout about how they are going to report it when something happens.

Slightly off topic, but kinda related
There's a scamera van sits on a main road next to my factory. Directly in front of the factory is a rat run; folk do silly speeds down it to avoid the scamera.
On at least one occaision that the scamera was sitting and catching no one, some tt has driven the rat run so fast that they have failed to negotiate the junction at the end of the rat run and has ploughed into the factory (there were sevaral more reported that the scameras have ignored)
The last BMW driver Senna, while the scamera was 30 meters away, hit so hard that he shunted a 2.5 tonne forklift 3 meters. At which point the scamera van drove off - completely oblvious.

I'll back the OP's point that scamera van drivers are clueless twunts.

Personally I think everyone thats get issued a NIP via a scamera partnership or gatso type device should excercise their legal rights and take it to court. Would take what 2 days before the entire system ground to a halt? A bit of people power to show the Gummint they should be doing OUR bidding not the other way round.

only if I've had so much to drink they chuck me off the bus

As I said earlier I don't think the scamera van driving was as bad as is being made out.
In fact I'd go as far as to say it was on a par with a lot of driving seen on our roads today.
Had I been that van driver (God forbid) I may have (unlikely, but I MAY have had I not been such a perfect driver that I never make such errors) seen the OP's car steaming up behind at a rate of knots only to vanish in my blind spot (or the contact position as the OP likes to call it) I may have been watching my wing-mirrors like a hawk trying to determine just what he was thinking of doing. I may even have 'blipped' the brakes in the hopes he would drop back into view before the turning I intended on taking.
In fact I may be so engrossed in watching out for an overtaking manoeuvre from him that I almost miss the turning I needed and do a bit of sharp manoeuvring of my own complete with late signalling after seeing him reappear in my wing-mirrors momentarily with his right turn indicators ablaze...Kinda like..."WTF! is he overtaking here? Phew! Thank God he's just turning here as well...Oh bugger forgot to indicate... nearly missed my turning too...that's better he's backed off a bit now..."

That's a pretty good assessment, the only thing I'd take exception to is that

@0:36 brake lights come on when van is a couple of lengths short of the island. He still has to pass the green direction sign at this point.

@0.:38 right indicator goes on as van rear passes end of hatching and right turn lane starts. It seems to my eyes that
this could be earliest point at which he could see the white direction signs on offside beyond the actual junction.

@0.39 OP moves quickly into right turn lane.

So pretty much as above, except at the "Oh bugger is he overtaking here, forgot to indicate..." moment in oldsoak's narrative, the indicator had already been on for a few seconds.

At that point to establish position in right turning lane, and then make a right turn would have been quite inelegant imo. Far beter just to make yourself wide as possible and make a single smooth right turn, or just abort.

No doubt at that point in case of an abort the tenor of the thread would have been, "Look at this scp van, signalling and then changing his mind."

We all hate scp, but come on!!!!!!!!!!!

Let's have some videos of really crap driving, instead of this bks, eg approaching green light, goes to amber, I stop normally, not even pushed to halt behind the line, guy some way behind me, pulls out, plants it and goes through three seconds into the red. Audi......

If it did you would have known about it by now. As you are asking the question it's plain that the answer is...no.
It was a lay by, if there was room, you had every right to park there, just because a scamera van was also parked there attempting to catch the unwary doesn't change that fact.

If what you say is correct, i.e. that you got a torrent of unpleasant abuse from him, and you are innocent of any back chat, a complaint is in order imo.

Unfortunately the first point of call will be the Pratnership Manager.

Email them, shouldn't take you more than 10 mins..