We have a local pay as you feel place which is trying to prevent food waste, and another place which calls itself a "top up shop" which might be ideal for circumstances like this - you pay £2 and can get a full bag of groceries.
Worth thinking as well about how far you drive - with petrol as expensive as it is, if you have a bike mouldering in the shed that you could get out, dust down and pump up the tyres that might save some cash.
Obvious things as well like not planning anything other than free days out. Worth thinking about free things you might not otherwise go to so you don't get bored and give up - stuff like a local museum maybe, or Geocaching or going to the local woods with hundreds of snowdrops. Going to the library instead of buying new books.
And maybe thinking about the holiday you have booked - is there anything you can take with you so the money you spend there buys you the maximum enjoyment. E.g. making sure you take snacks/drinks/a cool bag or whatever so you can make the most of the spends on the things that will add most value.
Are things like your internet out of contract or anything? Money saving expert sometimes has cashback offers when you switch provider. Any subscriptions you could cancel? E.g. audible can be at least temporarily replaced by using borrowbox or Libby, generally provided by the library for free. Phones out of contract where you could switch to a cheaper provider?
Worth having a clear out and selling any clothes on Vinted?
I reckon this lot plus the many recommendations for cheap recipes up thread will get you most of the way there. I feel like MSE recommends something like a money MOT where you check all this stuff out once a year.
Worth thinking of things like onions from Asian stores or the market depending where you are. I saw a massive sack of onions the other day for really not much, especially compared to how expensive they are at the supermarket. The market is much better value round here.