Moorendman asks 'If people shop elsewhere because they cannot get what they want in Marple currently, why would they walk 400 to 500 yards to a more depleted central area to shop for goods or services they can't buy in a Tesco or Asda situated in Hibbert Lane?'
Let me try to explain how the numbers might work, and why I don't accept that the centre of the town would necessarily become 'depleted'.
We know from reports of the college's property consultant's findings, and indeed from our own intuition, that more Marple residents go elsewhere to do their supermarket shopping than do it in Marple. So purely for illustrative purposes, and using nice round numbers, let's assume that out of the 23,000 residents, there are 10,000 supermarket visits per week, and that of these, 4,000 are in Marple and 6,000 are elsewhere. And let's also assume that of the 4,000 visiting the Co-op, 25 percent (1,000) go to at least one other (local) shop on the same trip.
OK. Now if a new Tesco or Asda appears in Hibbert Lane, let's assume that two-thirds (4,000) of those currently shopping outside Marple shop at Hibbert Lane instead. And let's assume that the Co-op loses 50 percent (2,000) of its customers to the new supermarket. That's 6,000 customers per week at Tesco/Asda so far. On top of these, we need to add visiting shoppers from neighbouring areas (Romiley, Disley, New Mills, Offerton etc) - maybe 2,000 weekly? That produces 8,000 weekly shops in total at Hibbert Lane.
Now let's try to estimate 'spin-off shoppers' - those who visit at least one other (local) shop during their supermarket trip. We'va already assumed that 25 percent of Co-op shoppers may do this, so that produces 500 of the Co-op's depleted number of 2,000. Now Hibbert Lane is a bit further from other shops than the Co-op is, so let's assume a cautious 10 percent (800) of Tesco/Asda shoppers also visit at least one local shop as well. That gives a weekly total of 1,300 'spin-off shoppers' in Marple - a 30 percent increase over the current estimate of 1,000.
This is all speculation, of course - just like almost everything else on this thread
And all the above numbers are purely for illustration. But what I believe it shows is that although a new supermarket in Hibbert Lane would take some business away from other shops, this could be more tha offset by completely new business coming from people shopping in Marple who did not previously do so.