The very existence of the supplied "week of food for school lunch" that is being supplied instead of a £30 voucher shifts the Overton window - normalises those quantities. We need to shift it back. So here goes - what could you do for £30? 1/n
https://www.abelandcole.co.uk/medium-fruit-veg-box-organic At market rate, Abel and Cole do this box for £20 - 7 portions of veg, two of fruit, all organic. The other £10 would give a decent portion of organic meat plus delivery.
My wife volunteers for @TrussellTrust foodbank. She just totted up what one person would be given for 3 days food, and reckons it would cost £10-15 to buy. https://www.trusselltrust.org/
@Riverford do this veg box https://www.riverford.co.uk/seasonal-organic-boxes/organic-veg-boxes/box-7-medium-vegbox-less-roots - seasonal, organic, easy-prep for £17, or this one https://www.riverford.co.uk/seasonal-organic-boxes/organic-fruit-and-veg-boxes/box-10-large-fruit-and-vegbox-original for £23.55.
https://www.oddbox.co.uk/ will do a large box of misshapen "rescue" fruit and veg - 9 veg, 4 fruit - for about £20.
Thinking about supermarkets, even, @Morrisons will do this box https://www.morrisons.com/food-boxes/box/5-meals-to-feed-a-family-of-4-subscription-box for £30 (or £28.50 as a subscription).
If you know of suppliers who could do better than the examples we saw last night, please add them, or tag them.