Third light of the upper row of the stained glass window in the staircase with the coat of arms of de Helles a Becket and Sir Henry Colet. “Presented to the City of Londonderry by the Worshipful Company of Mercers. London: A.D. 1912”. The stained glass window was manufactured by Campbell Brothers in Belfast, destroyed in 1972 by an IRA bomb, and restored by Calderwood Glass, Newtownabbey.