The fantastic ‘Hampshire Treasures’ resource gives the following info – “Frankenbury camp, south of Folds Farm. Covers 11 acres. Steep natural slopes on west and south sides. North east sides defended by rampart and ditch. Original entrance has since been widened. Scheduled Ancient Monument no 122”
Various Iron Age Potter has been found nearby - at permanent caravan site in an old gravel pit (circa SU165142) and on farmland east of Criddlestyle (circa SU161142). Now in Salisbury Museum.
NB – A place called ‘Sandy Balls’ lies just due south.......but it’s nowhere near Studland Bay