Haven't read your thread yet, ami, and others have probably said: shop at aldi. Moneysavingexpert and Which say you save 30% compared to Sainsbury's & Tesco. It is better quality than Asda (in general) and still cheaper.
Aldi shopping is different from 'normal' supermarket shopping. It doesn't carry known brands - though most of the products are the same ones with different labels on - and stocks vary from week to week. If you're a strict meal planner you'll have problems because of the variability, but broad-stroke planning works fine.
Cook for the freezer. I've never worked out why it's more cost-effective to cook double and freeze half, but it is! As I'm on a tiny budget, I use the slow cooker a lot and have a freezer full of casseroles, bolognese & so on. I've just discovered you can bake in the slow cooker and the microwave! The less I use the oven, the more I save :) Don't bake things that are cheaper to buy, like biscuits and everyday cakes (unless baking's your hobby, of course).
Stop buying a different cleaning product for each purpose. Stop buying wipes for this & that. Use microfibre cloths with a small squirt of product. Close the nozzles on cleaning products; they evaporate if left open. Keep an eye open for cleaning tips: WD40 and glycerin clean masses of things; practically everything else can be cleaned with soda or vinegar!
Don't buy extended guarantees on white goods. If they break down, consider replacing them with second-hand ones: at around £60 per appliance, it's often cheaper than a repair.
Before buying household items from known stores or catalogues, look on ebay and amazon. Same with kids' stuff. Browse pound shops - there's often a gem amongst the tat! For clothes, find out where your local outlet shops are and use them.
You get good, weekly discounts on cinema and other family activities with Orange mobile; I imagine other providers do something similar. Look on community noticeboards and even the council offices for things to do locally with DC at low cost.
Sorry, that was miles long! Hope I haven't duplicated too much ...