Any question answered...

Is it wishful thinking to imagine that if I collect video evidence of the ridiculous number of people who overtake on a particular blind curve through an overpass that the council will actually do something like, I don't know, install a ticketing device for when people do it?

The Council wouldn't do traffic enforcement. You'd have to identify a specific offence if you wanted the police to do something, e.g. crossing a solid white line if there was one. You could submit this via the roadsafelondon mechanism.

You could contact your local LCC group to ask about any campaigning history at that location. It's likely that it's been flagged up as a problem before and together with them you could start a campaign for design changes. PM me if you need any more advice.