Where does the Queen shop?

When we do our work on the Geography of Food, we explore where our food comes from.
This Telegraph article outlines the companies that hold Royal warrants for supplying the Queen with her food.
I used to live on the edge of the Sandringham estate for 12 years, and used to patch a butcher in Dersingham that had the Royal Warrant attached to the building. He provides the Royals with their meat, and sells meat from animals reared on and near the estate.

It has a link to the ESRI UK map that shows the location of these companies.