Just bought a Halfords 40 litre coolbox , from eBay. Halfords don't sell it anymore, but v good reviews. There are used and new ones on eBay. Returned from camping last week. 2 different friends had this one. Fill it at home. Milk and something to make the first meal out of, for example. Extension lead that plugs into your car cigarette lighter, so keeps it cool , whilst driving , on way down to campsite. Then, when you get there, it has a different extension lead, normal plug, so plug into your electric hook up. Both friends said it was fab. Good for storing that extra bottle of wine!! Can't wait to start using ours.
We used a coolbox but upgraded to a table top fridge as we found we didn't have enough space for all our wine and beer food. Would really recommend this as although bulky, can be filled when travelling.