We're about £60-75/week for two adults, one teenager and two under 10s. I tend to use the 99p stores A LOT! I love 'em. Everything in the store for 99p and they've got stuff I actually use! Soap, toothpaste, cleaners, bin liners . . . yadda, yadda, yadda. Gotta be careful cuz it IS an impulse buyers nightmare (dream?) but armed with a list it's a pretty great pound stretcher.
I've found that buying good food - ie fresh from butcher or green grocer - makes a real difference in how much we actually eat. Having tasty fruit, veg and meat to cook with and snack on means lots of flavour and less need to snack on more expensive things.