If you are considering spending money on a good car type fridge the best is the Engel, beats the Waeco range hands down. They are only electric though, they will run a good while on a battery (I have never found out how long). They are settable to freezer or fridge temps. Try to find a supplier of both and compare them, ask the dealer his opinion.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.