Good to see you got home ok.
That is the sortest ride out I've ever been on (1/2 a lap of a roundabout to reach the scene of an accident).
Get a full set of details ready for the insurance company when they open on Tuesday, full description of the scene and how the accident happend, photos etc. (happy to give it a 'once over' if needed), then get a detailed statement on record with your insurer & send the details by post. Ask them what they will do, how long it will take (if they say weeks/months, ask how it can be sped up as it's a very simple case), then bother your insurer regularly for progress.
Also get to the docs and obtain an opinion on your hand. If you do end up being shafted by the old dear's insurer, you can make up your loss with a personal injury claim. It might be worth contating your legal insurers as they'll probably have a set up in place for this sort of thing.