I live in the UK. I have been a visitor at the museum since 1971, when the collection was housed in the Stedlijk. The quality of merchandise has improved enormously over 46 years! But your staff at the online shop are your best asset. They are friendly, courteous and helpful. I would single out Madelon Spijker, whose customer service is outstanding.
Improvements or suggestions
It is sometimes difficult to understand the design of the website. I buy diaries every year. Last year, I spent a long time in failing to find them on the website! Madelon Spijker's help was invaluable in tracking them down.
You used to use Hermes for deliveries in England. They were not efficient. You now use DHL and, since I have a current order with you (June 2017) , I shall see whether they are any better.