How about taking new potatoes for boiling up and copup with mayo and add acan of tuna and some french beads you cooked before you left and a small tin of balck olives?
Or subsitute the above tin of tuna with some already cooked sausages and some cherry toms?
Take with you par boiled potaotes, then slice em up, chuck em in a pan with some chopped up bacon, cherry toms, and serve with crusty bread.