I did a short stint serving behind the counter in the shop, which I have done only once before as a way of seeing what it’s like, so to speak, on the shop floor;  watching visitors browse amongst the product – picking up pencils, chocolates and beer, as well as the handsome Charles I catalogue, the biggest seller by far.   Far more tourists than I had expected, but that may be just because it’s such an international exhibition – great works of art bought for Charles I by his agents – and a privilege to see so many major works of art, which are not necessarily familiar to the average exhibition goer, including many from the royal collection.