My DH is over 70 and has a heart condition, so we started to isolate before mid-March. Our first few bills during this time were huge because I was pretty low on stock and had trouble getting online shopping slots, but it has all balanced out now.
DH likes simple food so we have roast chicken which reappears as risotto, fajitas, chicken with jacket potatoes etc. Also batch cooked mince which becomes bolognaise, cottage pie, and lasagne. We always have eggs for breakfast and now sometimes have tortilla which can reappear for lunch another day. We've rediscoverd the kipper!
I'm lucky because I've always alternated my online shops between Ocado and Waitrose and have been given priority slots by both which means I can still have a normal sized delivery every week and include items for older neighbours who need them.
The thing I miss most is going to Lidl every week to buy my fruit, veg and free-range chicken. DH misses their NZ sauvignon blanc!