Very considerable repairs and alterations were made in the choir during the years 1742-43, under the direction of Mr. Sloane. While they were in progress, for the space of a year and a quarter, the dean and chapter attended service at St. Nicholas Church. New stalls and pews were erected and the partition walls wainscoted; a pavement was laid "with Bremen and Portland stone beautifully disposed;" and an episcopal throne was presented by Bishop Wilcocks and placed opposite the pulpit, where the present throne now stands. Much white-washing was done at this time, even the numerous Purbeck marble shafts being covered with it. In 1788, however, they are mentioned as polished once more and restored to their original beauty. From shortly after the Restoration until about the time of these alterations, the inclosure of the bishop's consistory court had been situated near the west end of the south aisle of the nave. It was now removed to the Lady Chapel, where it remained until well on in the present century.
The steeple had, at last, to be rebuilt in 1749. Mr. Sloane's model of its woodwork was for many years preserved in St. William's Chapel, and has since been kept in the crypt, where it still remains, but in a very dilapidated condition. In 1763 the northern of the towers flanking the west front was considered to be in a dangerous state, and was taken down, together with the upper part of the north aisle end beside it. It was rebuilt soon afterwards. A bequest of £100, in 1765, by Dr. John Newcome, dean of the cathedral and master of St. John's College, Cambridge, towards the repair of the fabric, was probably intended to help this work. The new tower was professedly a careful reproduction of the old, but its incongruities have formed one of the reasons for the recent thorough renovation, instead of mere repairing, of the west front. It was only carried up to about half its former height, and was there, with the aisle end, finished off with battlements. This was all done before 1772, as an engraved view of the west front in that year shows. The southern tower is in this view still unlowered, but it was cut down, to match its fellow in height, soon afterwards.
For a long time previously the outer walls of the south choir aisle and south choir transept had occasioned great anxiety. They were not buttressed originally, like the similarly situated walls on the other side of the church, probably because they had the cloister and other conventual buildings to support and shelter them. Several attempts were made, in particular, to render the transept secure. A first was by the fixing of wooden ties, with large iron bolts, in the main timbers of the roof; a second, in 1751, in pursuance of advice by Mr. Sloane, by the raising of two great brick buttresses; and a third, about twenty years later, by lightening the roof. These were useful for a time, but, as the wall was still evidently declining, Mr. Mylne was consulted and, by his direction, piles of bricks were erected in the undercroft, and other methods were used to discharge the weight of the upper works. These schemes were brutal and inartistic. Though they answered their purpose for some years, they were afterwards found to be doing harm rather than good.
