Family food budget?

After a trip to Tescos and an additional £32 spent I am wondering what budget we should be aiming for?

The reality is I have no idea what we should spend, with all the recent food price increases I don't know what is reasonable - how much would you say to feed a family of 6 healthily for 1 week?

I know a budget would normally be 'what you can afford' however, I want a challenge to see how well we can do. I am finding it fun thinking of simple, cheap and healthy meals.