PowerSwitch

This company may be of interest.

https://preppersshop.co.uk/

They offer a wide variety off long life foods, bulk packs, camping supplies, archery equipment, and related goods.
The bulk packs of sugar and pasta caught my eye, not in fact any cheaper than from a supermarket, but a single 25 kilo sack of sugar is easier to store than numerous small packs.
Also buying 25 kilos of sugar from a high street store might attract more attention.

No direct experience of this supplier, a respected member suggested them elsewhere in these forums, and I felt that the information was worth repeating in a dedicated thread.

I confirm that I have no connection with them.

I'd find 5x5kg bags of sugar easier to deal with than one 25kg sack. Also less like putting all your eggs in one basket.

For bulk food purchase, I'd recommend Suma or Essential Trading. Down side is high minimum order value but up side is bulk packaging of *high quality* food for the price of regular supermarket food.

I'd be very wary of buying/eating significant quantities (US made) army ration packs with a whole paragraph of ingredients! Not so wholesome.