In 2005 Dunston wrote:
This site is known as 'Glyn' in Frances Lynch's 'Prehistoric Anglesey'.
In the excavation report for Benllech states that Benllech and Glyn are different tombs. Judging by the images on TMA and the info in the Benllech excavation report the site on TMA is in fact Glyn and not Benllech.The correct grid ref for the real Benllech is SH 5190 8275