Oh, and of course a 5L bottle of water for keeping the rad topped off! Also a handful of oily rags and several pairs of work gloves!

Interesting topic, most normal car owners nowadays would display a face of confusion/disgust if it were suggested that they should carry a tool kit around with them for roadside repairs! I keep a large ammo box in the back with the standard bottle jack and breaker bars, then the spanner set...