I emphasis with the emotional stress put on you by being a victim but also as an ex-offender and please bear with me why I offer my thoughts. I am an ex-offender and I am struggling to change the view of the majority of society that "anyone" can offend but they can also learn from that to become what we term as "rehabilitated".
First the actual details of the offence only matter if you report it - an action I would recommend. See the end for actions I would do.
We would agree the percentage chances of you finding and therefore talking to this individual are not reasonably in your favour, so you cannot explain the consequences of offending e.g. the circle of their victims grows and encompasses more people than they may think. Therefore and as we all know, you will not have the chance to offer your words directly if the authorities are involved. If however by writing a positive - non condemning - impact statement to the Judge, the outcome may be surprising.
In my view your considerations should be more concerned with understanding your own emotional long term damage!
As you mention, you feel inclined that you must in some way help the individual's future i.e. not getting a criminal record, which is understandable due to the emotional effects on you by your past. The question to ask yourself "is this just your quilt making this option more prominent and favourable?" Only you can answer that if you are to be honest with yourself as your words do not suggest your motive is revenge.
Your words suggest you understand the impact of any offence on the "wide circle of victims" created, the impacts may be long term and not recognisable at first but they will be there. We all know each one of us ex-offenders at some time feel aggravated, frustrated and selfish by comparing our fate to what we perceive as "the luck of the draw of others". I know I do. That moment could be the time your decision will reappear in either in its ugly or pleasant nature. By this I mean, whatever your decision, at some time in the future when your past affects you, you need to not view this decision as ugly and so regrettable.
Whatever your decision, I hope at some time in the future you will still be happy with it.
Evidence gathering ideas:
The video evidence is there - for how long is questionable so you must contact the pub and other buildings ASAP before they delete it. You have factual evidence from the driver of the other car, get them to write it down ASAP before any details could be questionable due to memory loss / time. In this time of under resourcing you having this will strengthen your case.
Learn from yesterday, live for today, hope is for tomorrow else what is left if you remove a mans hope.