Can I REALLY feed the family for £50 a week??

I've been here before. I KNOW its possible because I've managed it. However my major two camps which I flit between are being thrifty and being healthy. I'm not a foodie. I really struggle to go to restaurants and spend money on eating food. I can't buy special cheese or posh snacks or even crisps - food is just an essential item, a boring thing we have to do... and every time I get to the check out I'm already working out how many tops I could have got instead of all this dull food. Its the way my brain works and I've not met many people who get this! So when I'm not obsessed with saving I'm busy being obsessed with nutrition. I love it when I know I've made meals from scratch, I know every item is unprocessed and I can pack 7 different veg onto my children's plate. At home we let the children choose 2 things they don't have to eat. They both chose leeks and mushroom. If either of those is found in their meal they can leave it but everything else has to go. They can submit a request to change their chosen vegetables but this has to be done in writing and doesn't get authorised for 24 hours. We've found this works to stop a sudden change to celery mid meal when there's no mushroom around. Anyhow, I've found a way to chop mushroom so that it doesnt look like mushroom and they eat it (and I tell them afterwards because I'm slightly honest) But I love it that when there's something they're struggling with we get out the Food Doctor book about superfoods and read up about what they're eating and what it helps with. They don't just know about eating their greens...but which shades of green will help with different aspects of looking after their bodies. I love how amazing food can be for they way we feel, the way our minds operate and how it can increase our effectiveness if we use it well...and do the opposite when we don't. I've never taken my children to McDonalds. I'm never surprised when I see pictures of chicken brains in a KFC and I've explained about the pig snouts and ears you get in frankfurters. So long as they are educated and have had a healthy grounding while I'm in charge of their meals! Apparently eating about 15-20 blueberries at the end of your lunch more than doubles the effectiveness of your work in the afternoon. I tried it and it's true. There's nothing worse than the afternoon lull. The trouble is blueberries are expensive. How do I fit 20 blueberries a day into a £50, family of 4 for a week plan!?
So thats the aim. Instead of hitting the financial target by mainly eating value pasta and homemade tomato based sauces I NEED to get the right variety and goodness in there too. Well... February is a short month. Seems like the ideal one to give it a go. I've £200 just arrived in the bank for grocery shopping and I'm enthusiastic so lets give it a go!? It is, admittedly, already the 5th... but I've not bought anything in Feb yet and my grocery budget also has to buy things like shampoo, nappies (still:S) and urgently a load of washing powder (which is always loads!) so its a fair attempt.
Ooh and pretty soon we wont have to buy garlic as we've just grown some! Thats at least 70p saved right there!