Many years ago, in the school CCF (70s - & a state school), we had "compo" (composite) rations. We would always over-order for weekends away and stock up the radio room with the surplus. Mostly tins, sachets and tubes (jam and margarine both came in tubes like toothpaste tubes iirc). Sugar came in a tin, as did boiled sweets and chocolate bars. Mock turtle soup & mashed potato came in sachets. Stuff like beans and sausages came in tins, as did milk - condensed. I'm not a tea drinker but I think tea came as an instant powder.
I've been only using campsites the last few years and so don't need such ready-meals but I am contemplating some bivvy-bag overnighters and would very much like a few of the backpacker type sachet meals to fall back on.
From what I've seen/read about what's available, I'm not so keen on the military stuff - dubious suppliers/sources (I gather most military stuff is not supposed to be sold to the public) and not especially compact/lightweight for the calories. The prices seem too steep too.
I've had a quick look at the Firepot brand and similar and they look quite good though not cheap either (but, I think, comparable to the military stuff and no dodgy dates or source). At least they do a 1000 calorie sachet, which is the sort of thing I'd want. Supplemented with biscuits, peanuts, cake, pasties etc., and I reckon that'd do the trick. A pub meal would help too