I've lost count of the number of times I have been disappointed by supermarket-bought strawberries. Often lacking in the taste department (and usually not even fully ripe!), they're a bland, hard offering next to the home-grown alternative. It's no wonder really – these strawberries have to travel long distances and must be able to withstand the knocks that go with it. It means that the varieties of strawbs destined for stores must be hard-skinned and exhibit a long shelf life. This is fair…