The description in the NMR for Maen-y-Parc (available through Coflein) includes three stones, imaginatively labelled A, B and C:
Heights are between 1.6 – 2.3m. B and C are built into field walls.
Local placename, Clyn Saith Maen, refers to seven standing stones.
Not exactly a detailed description of the site. Presumably Maen-y-Parc ‘A’ is the stone that’s 2.3 metres high. Collectively all three stone appear to be called the ‘Gate Standing Stones’, presumably after the farm to the south. The eight figure grid reference given for Maen-y-Parc ‘A’ is SN11133032.