Frettenham is a civil parish in the English county of Norfolk. Known in the Domesday Book as ‘Fretham’, Frettenham is located six miles north-east of Norwich, surrounded by countryside. The village is well known for its rich farmland. ~Wikipedia.
I could not locate this one, there is a ‘Post Office Road’ in Frettenham today though, so I assume it was along there somewhere. There is a building that looks a similar shape from the aerial images but it is obscured by hedges.
Kelly’s 1900 Directory of Norfolk shows the postmaster then was Charles Garrett. Going back a little to 1891 he was living in Fryers Road (which I cannot find modern reference to – maybe that road was renamed to Post Office Road ?). He was occupied as Post Office/grocer and aged 32.