The marvellous ‘MAGIC’ (https://www.magic.gov.uk) map site has this further information:
The monument includes a bowl barrow set on the crest of a gentle east-facing slope above the valley of the River Wylye. The barrow mound is 30m in diameter and stands 4.2m high. A central depression 1.7m deep may represent early exploration of the barrow mound, probably in the 19th century. Although no longer visible at ground level a ditch, from which material was quarried during construction of the monument, surrounds the mound. This has become infilled over the years but survives as a buried feature c.3m wide.