Cadw appointed Ferrier Hart Thomas and David Odgers Conservation to survey, provide design information and specify in detail the works stonemasons need to carry out.
Penododd Cadw Ferrier Hart Thomas a David Odgers Conservation i gynnal yr arolwg, darparu'r wybodaeth dylunio a nodi'n fanwl y gwaith y bydd angen i'r seiri maen ei wneud.