The problem is with tesco or any other big brand store helping a local community is theres nothing in it for them. They have no real benefits for doing so. To get them to do anything what you need to do is tell them what's in it for them instead of how good it would be for the local community.
e.g tell them how it would improve promotion, or it could be a low cost promotion in the local area
tell them it would improve their links with the local community etc, etc
Its that sort of stuff u want to try.
Also it helps if you know the manager at the store. the other thing is who are you contacting, the head office or the manager at your local store, sounds mad but your more likely to get a positive response out of the manager!!
Theres so much pollution in the air now that if it werent for our lungs there would be no place to put it all. ~Robert Orben