Good luck spotty 
Welcome to all new folk and Happy New Year.
mortil - if it helps, I have teen DC, so can understand how you food shop goes less far than when said DC were younger! I would say that my food budget hovers around £120pw, included in that figure would be beer/wine, toiletries and cleaning items. We eat packed lunches too, although DH will have lunch on expenses if travelling for his job.
Things that have helped me are getting my shop delivered each week, rather than being tempted at the supermarket. One 'cheap' meal a week such as egg and chips, omelette, jacket spuds, risotto. I often do a cheap pudding such as crumble or banana cake to supplement that night.
One veggie meal a week. I would have many more but DH doesn't think it's meal without meat! Meal planning helps. I freeze a lot more now, even small bits of stock and leftovers. Slow cookers work well.
Also invested in a soup maker so bits of leftover veg get used up and DD takes to school for lunch in a flask. The soup maker was £50 admittedly, but it also blends and juices.
Also have fruit and veg delivered from the local market, which saves loads on supermarket prices. Cleaning products are from pound type shops. Meat from local farm shop, which is far cheaper and much nicer.
NSD today. Went to a friends house last night and partied but feel reasonable ok today. DH and I are doing 'dry January', we drink too much, our main vice, and both need to cut back.