Sir Anthony's garden (4)
I believe the answer is:
eden
I believe this is a double definition.
'sir anthony's' is the first definition.
(I've seen this in another clue)
'garden' is the second definition.
(Garden of Eden in the Bible)
(Other definitions for eden that I've seen before include "Adam and Eve's garden" , "Former British PM - unspoilt paradise" , "Place of unspoiled beauty" , "The original garden?" , "Former prime minister" .)