 Complete the following phrase:  A windmill was standing on this site in 1847. Vale Windmill is a five-storey tower mill that was built in 1850. Photographs show it to have had four patent sails mounted in a canister, and an ogee cap similar in shape to those found in Suffolk, winded by a fantail. The mill had a stage at first floor level. It was converted into an artillery observation post by the 