Wiki:
On the acroteria of the pediment are three statues by John Smyth: Mercury on the right, with his Caduceus and purse; Fidelity on the left, with her finger on her lip and a key in her hand; and Hibernia in the centre, resting on her spear and holding a harp.
Great building, pity it is not easier to see, would be good on a square.