Co-ops
There are over 2400 of them in the UK Margaret. Of those 2000 are Convenience stores which is the fastest growing sector in the UK. The Co-op through its various manifestations is one of the largest.
Aren't there any on South Tyneside? Bear in mind that the Co-op also operates under the Nisa brand in certain locations.
There a several Co-op Convenience Stores close by me in South Derbyshire. They invariably have a P.O. and other services like "parcel lockers"
I'm afraid your Coop Membership Number from J & H Days is long gone......like you I remember my Mums and my Granny's to this day.
Some of the Co-ops still operate schemes but not all!