Yes Tricky, the 10p fee is refunded (I think it's still 10p), but the problem is forgetting to pay it. One should not forget, I know, but a little absent mindedness, can cost a lot even though you might be using local traders.
Incidental, I was chatting to a local resident yesterday about this very thing and he told me that parking charges on the co-op car park were not enforceable, as apparently the land was designated for exclusive use of Marple residents without a charge. I don't know if this is correct, does Mr Noble know the answer to this?