You could be right! I don't have the answers, but the children who's parents spend food vouchers to feed their children on booze and cigarettes are probably not getting cared for very well anyway.
Personally I believe there's enough people on furlough that have signed up to be volunteers that haven't been called upon. Why don't they take it local, use local people and I'm sure supermarkets would help where the parents have a shopping list (limited choices but variances for differing dietary needs) that they can chose from to value of £30 this is then shopped for by the volunteers over night (when its quiet) delivered next day to the door. Bill from supermarket goes to the school to pay or whoever does it. Volunteers get their fuel bill paid or they use a school minibus, in fact local hire companies would probably help