It's not often that a simple trip to the grocers leaves you vulnerable to a bout of the giggles, but with Arkwright and Granville behind the counter it's a c-c-c-certainty in Roy Clarke's iconic sitcom. David Jason learns at the foot of the master, serving his hilarious apprenticeship with Ronnie Barker's stammering shopkeeper. Ger-Granville! Fer-fetch yer cloth!