Wow, such a range of conflicting views here...
My 2p FWIW:
a) I think the police probably WOULD be interested and WOULD convict provided there is no doubt about who is driving. Not so sure if there's any doubt or if they need further evidence. In my experience Plod likes low hanging fruit and this looks like a good chance of conviction(s) for negligible work on their part.
b) A purely personal viewpoint but I wouldn't just walk away and leave it. Some would, but it would irk me to feel that pondlife like this had 'won'. However I would rule out a civil action as too costly & not worth the effort.
c) It's been said already but I think you need to decide upfront whether some sort of financial compensation OR inflicting pain is most important.
d) I think compensation is viable but you need to pick your words carefully, under no circumstances link any failure to cough up on their part to other 'consequences' and perhaps have a mate to witness the conversation in case they try to turn anything against you. If you want to take this route, I'd perhaps emphasise the wear & tear on costly tyres & probable maintenance costs down the line from ragging a highly tuned engine from cold to support the principle that you've suffered a loss albeit one that's hard to quantify right now - rather than just 'profiteering'
e) Maybe the biggest damage you can do them is via online reviews, social media & the local press. Also any trade bodies or accreditations - are they for example AA approved? I suspect they might lose that kind of thing if AA (or whoever) saw your video. BUT beware falling foul of libel laws. There have been a few cases lately where bad businesses have sued and won against a negative review - basic rule is don't say anything you can't substantiate.
f) I doubt that your fear of retribution is justified. You say they might see your car around and scratch it ...but do they know for sure whether your dashcam records video whilst parked? They may not be the sharpest tools but risking being caught on camera AGAIN whilst inflicting criminal damage would surely be senseless.
g) I think maybe I'd show them just a little of your recorded footage. Don't reveal all your evidence. Let them sweat over what they said or did. It's entirely possible that they'll fear that you have something even more damning than you do.
Good luck whatever you choose to do
What other speeds did they get up to?
