In 2018 the National Trust published some of the results from a geophysical survey in the vicinity of the Beacon and Castle Field.
“For centuries, a field to the north-west corner of New Winchelsea has been known as Castle Field. Here, the magnetometer survey uncovered a 40m diameter circular ditch and bank enclosed within a large ditched enclosure. With the help of experts at the University of Exeter, the team was able to identify these as the remains of a castle’s earthworks: King Edward I’s castle.
The map reveals more about life after Edward too. The town ditch, constructed around 1415AD, can be seen to push Quarters 5 and 11 outside of the town – in effect sacrificing its inhabitants to French raids. A post medieval windmill (postmill) was highlighted via a circular anomaly containing an X. To the east, a clear curved feature is the remains of a medieval stone-built windmill.”