I had never noticed this building before it just caught my eye today, so I took the shot and looked it up.
This description has been taken from the Amersham history web site: The central flint and brick building designed by George Gilbert Scott was built in 1838 in Tudor style with unknapped (not split to show the dark stone inside) flints and red brick. It was originally the Workhouse for the Amersham Union of Parishes and then became Amersham Hospital. As part of the Hospital Private Finance Initiative, when a new hospital was built recently the old part was converted into private apartments. The building together with the gatehouse and the front boundary wall are all listed grade II.