The fantastic ‘Hampshire Treasures’ resource gives the following info on this scheduled ancient monument, no.430 – “ 135 yds. north of the Roman road, on the Hants/ Wilts border. 38 m. long by 24 m. wide. Ditch visible on west side with only vague traces on the east side O.S.A. No. SU02 SW34.”
The OS map shows another Long barrow in Vernditch Chase about a 1km due North, but I can’t find any information about that one!