saxon or romanesque, perhaps originally a watch-tower to see who was entering the Deben estuary

one of a number of churches with a circular tower and nicely located on high ground near the Deben estuary. The romance: http://www.suffolkchurches.co.uk/ramsholt.htm
The facts:
http://www.britishlistedbuildings.co.uk/en-285492-church-of-all-saints-ramsholt-suffolk
More about round tower churches: http://dev.roundtowers.org.uk/visiting-round-tower-churches/