I'd second eurorescue. Bought a couple of times now for trips to Europe and seems pretty good value for short term cover. Never had to use it, but having once been stuck just outside Calais over New year's bank holiday with a broken throttle cable, I vowed I'd never travel without it again!
You'll need to get some headlight deflectors too if driving at night, which you're supposed to fit but know many don't bother. Also by law you should carry a single use breatherliser, replacement bulb kit, hi-viz jacket and your v5 reg. doc and insurance certificate - just in case you get pulled over!
Don't forget you may need to pay extra for equivalent insurance cover when driving abroad. Many policies will only cover third party abroad unless you pay extra to top it back up to fully comp.