Morrison's and Aldi are in Cheadle Heath, not Edgeley - it's nearly a mile away, and that's the problem.
The New Mills Co-op is certainly not large (it's much smaller than our Co-op), and crucially, it's too far from the town centre.
Incidentally, the small supermarket in the middle of New Mills (the one that houses the post office and has recently been a Spar), is apparently about to re-open as a Sainsbury's - presumably just the convenience store version, like the one in Romiley?