January 2009 - At the same spot as the above photo I found this cave which has some stone work and a gate which was locked. At the time I had no idea what the cave was used for.
January 2018 update - A viewer of my website has given me some very interesting history of the cave and a reference to an interesting article by Rodney Legg in his book Dorset America.
The caves date back to Elizabethan and Jacobean times and have been there since the time of the first introduction of the potato to the British Isles. They were dug as potato stores.
The tubers of white potatoes grown by the Incas were tasted by Sir Francis Drake in 1577 during his circumnavigation of the globe. In 1586 Drake took possession of some potatoes that were being carried as ships stores. They found their way via traders commissioned by Sir Walter Raleigh to England. Due to the Raleigh connection when he was living at Sherborne Castle the crop was first grown on the light soils to the west of Sherborne. After being dug the potatoes have to be stored in cool dark conditions to stop them going green and poisonous. This was initially a problem for the English growers but they solved it by digging a series of caves into the sandstone banks of the ancient holloways of this area. They were known as Tiddy Caves.