Was £400pm for me, DH, two toddlers and two cats. Includes all cleaning stuff, cat food, night nappies for DS (washables during the day), toiletries etc. We both work from home so includes all lunches too.
But from this month it's gone down to £350. I think this should be fine.
We cook from scratch every day, usually buy chicken or pork for a roast then casserole leftovers the next day and make a very bulked out casserole with pulses on day three.
Often have something like veggie burger and home-made wedges on a Friday night - cheap and cheerful!
We eat a lot of bread and potatoes as fillers so we can have less meat, eg bread in gravy after roast or casserole, garlic bread on the side of a pasta dish for a bit of variety, jackets with tuna and veg, homemade soup and warm, buttery rolls.
Healthy snacks for us are raisins, breadsticks, crackers and stuff - cheaper than cereal bars etc.
And we also buy whatever fruit is on offer and only buy cheap veg. Sainsbury's Basics big bag of frozen peas, lots of carrots, that sort of thing.
Would like to get it down further but can't see that happening as the kids get ever bigger and more hungry!