Denver is a village and civil parish in the English county of Norfolk. It is located on the River Great Ouse, 1 mile (2 km) south of the small town of Downham Market, 14 miles (22 km) south of the larger town of King’s Lynn, and 37 miles (60 km) west of the city of Norwich. ~Wikipedia
The postcard says this is the post office, I assume it is the long building. This is opposite the church. For the present day post office reverse up the road a little.