Hillock of Breakna

Some info not on NMRs from P.S.A.S. Volume XXXVII P.27 :-
In 1797 descibed as a circular tower of about 180’ circumference. The author of the P.S.A.S. chapter made it about 170’ in circumference, with walls 12’ thick and an int. diameter of roughly 30’. His investigations in 1879 & 1901 would explain the NMRS “an apparently old excavation” reference.
Also called The Brough, but known by locals as the Hillock of Brecknay after a nearby farm. In 1797 associated with a Sveinn Breastrope. Site then erronaeously labelled Earl Sveinn’s Castle, which then became ruins of Earl’s Palace on the map. Could it originally have simply been called the Castle, one of many in Orkney ?