Thanks, I've looked at that thread and will take a look at the code itself soon.
Should this become a more generalized general feature, with its own sub-menu - rewind on <x>, where <x> is a user-selectable set of events?
My current change is actually a bit backwards: it does the rewind when the car power goes off, rather than when it comes back on - after looking at the implementation of rewind on resume that looked a bit simpler. But I not wedded to that method.
Err - I'm in the wrong forum for getting into technical discussions, aren't I?