It's understandable that a lot of this discussion has focused on traffic issues, but we shouldn't forget those who can't, or don't want to, drive to do their shopping.
We need to remember that:
1. About 25% of UK households don't have a car.
2. The Marple area has the biggest % of elderly residents in Stockport (If you doubt it, look around you in the Co-op. I'm no spring chicken, but when I go there I feel young again

)
3. The potential supermarket site in Hibbert Lane is close to some of Marple's least affluent residential areas, where car ownership is therefore likely to be lower than in some other parts.
It's quite thought-provoking when you pass a big five-bedroom detached house in one of the leafier parts of Marple, and you see a 'No' poster in the window saying 'save our community'. There are two cars in the drive, and at least one of them is a 4x4. They can afford to buy their food at Waitrose or M&S, or maybe the Sainsbury's van calls here. And yet they want to prevent people who are less fortunate than themselves from being able to shop locally more cheaply. And they also want to stop our local college improving its facilities (but of course, it doesn't matter to them as their kids go to Stockport Grammar

)