Some excellent tips here. Thanks. It is slowly dawning on me that my self-catering will have to be carefully planned around the limited battery life for fridge and the need for zero washing up. Ridgemonkey & kitchen roll all the way. Spam + Primula?!
I’ll have to have another look at the thread about go to emergency meals...
make a meal plan roughly for each day :
example, chicken curry: Dry mix chicken tikka spice added to diced chicken, rice &Nan bread the later two are ambient and can be pre packed, the later can be pre made (raw) and placed in a poly bag then into the freezer.
Set the fridge up as a freezer initially, on the lowest (freezer) temp setting, pre freeze all your food In your home freezer.
transfer all food to the portable van fridge (set to lowest temp, 1 day before required) keeping running as a freezer, shortly before departing for the Festival, switch the temp to 3 degrees C. (Literally as your going to get in the van to leave home)
note: fill all available in the fridge space with can, bottles etc, to minimise air space.
the fridge will keep most of that food frozen for a day, then it will defrost for use and be kept chilled for a couple of days no problem. Freezing the food ensures the fridge has very little work to do to maintain the 3deg temp, filling every available internal space assists the efficiency of the fridge.
wash up at the van using hot water from a gas kettle.
edit ; your fridge should last several days (3+) if the leisure battery is pre charged at home for 24 hours (immediately prior to departure) and is in good health -& you limit draw from other devices by using power packs etc to charge whilst at site.
travelling to the festival, the leisure battery will be fully charged (if you pre charged it) when you arrive. When at the site and setting up increase the fridge temp to 4 degrees C which will further assist in reducing the battery usage.
get a cooler bag for placing evening drink into once back at the van to limit going in & out of the fridge