Have been really busy recently, so only got time for a quick post. This post is mostly about how to save money when buying lunch.
This is a tip that i learned a couple of years ago: the best time to go food shopping is 30 minutes before it closes. A lot of the perishables are marked down to stupid prices - bread at 10p a loaf and so on. With your newly acquired cut-price loaf of bread, you can then make sandwiches for lunches, rather than going out and buying them. It's cheaper and you'll always get the variety you want. During this time they may also sell packaged sandwiches at a really cheap price, worth buying if you don't have time to make a sandwich at night.
If you forgot your lunch and you need to go out and buy something to eat. (this relates to UK people only) The place i would recommend is Boots, their lunchtime meal deal is one of the best i have seen. For 3 pounds you can get a sandwich, drink and a snack. All sandwiches/drinks and mostly all snacks (chocolate bars, brownies etc..) are in the offer, so you could even choose a triple set sandwich and it would be included in the meal deal.
One final point about Boots, for those who like to eat lunch late (e.g. 3pm+), i know for a fact that Boots mark down their sandwiches to 75 pence each in the late afternoon, which is a bargain!