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Notes in italics from Hampshire and the Isle of Wight by Nikolaus Pevsner and David Lloyd (1967)
Yale University Press, New Haven and London.

The deanery in the Middle Ages was the Prior's Lodging. It lies south of the E range of the cloister, and the earliest part of it is in axis with this. 

This earliest part is the so-called cloister, i.e. a porch open to the S. (13th century). Three bays are open, a fourth has to the S the somewhat later spiral staircase to the upper floor. The porch has three steep arches of continuous double chamfers. ... The two upper stories above the porch have windows of two and four lights of probably the first half of the C16. To the E the C13 part has buttresses originally shafted. There is also a small blocked window with a shouldered lintel. 

Inside, the porch is rib-vaulted with single-chamfered ribs. They rest on Purbeck wall-shafts on the N side but on detached Purbeck piers, each of a core and four detached shafts, on the S side. These piers are placed at a sufficient distance from the porch piers to allow for small connecting transverse shouldered lintels. The E wall has blank arcading of two pointed arches with a super-rounded trefoiled arch. ... 

On the W of the porch and not in line with it is the C15 Prior's Hall, with five buttresses to the W and tall two-light Perp windows with one transom. To the S the hall projects beyond the porch, and there was there another window facing E. But this is now blocked. ...  

Lying back N a good deal and projecting boldly E is the LONG GALLERY  built by Dean Clarke (1666-79). It is of brick, laid Flemish bond, and stands on an open ground floor of varied supports: columns, then an arch, and then in the centre a composition of two pilasters with bulgy brick rustication. Above this bay on the upper floor is a Perp five-light window, re-used from somewhere else, and a pediment. The windows of the gallery l. and r. are of stone with a mullion-and-transom cross. The E window is an imitation of 1807. ...