Process supplies is closed on Saturdays too. It is a real shame that there is no high street shop available over the weekend when small fry customers like us are likely to visit.
I remember once a French guy with his London guide under his arm and a map in hand looking for his way to ... Silverprint. He had taken the Eurostar and come all the way from frogs land to go to silverprint. One frog to another, I obviously had a chat with him. For sure he is not the type of customer to come knocking every Saturday at the door, but still it means something for him to have come all the way.