The deanery of every cathedral and collegiate church upon the old foundation, except in Wales, and the three existing canonries in the cathedral church of Saint Paul in London, shall henceforth be in the direct patronage of her Majesty, who shall and may, upon the vacancy of any such deanery or canonry, appoint, by letters patent, a spiritual person to be dean or canon, as the case may be, who shall thereupon be entitled to installation as dean or canon of the church to which he may be so appointed.