On 17 January 1696 the Fabric Committee approved designs that had been laid before it and ordered them to be laid before the Grand Committee, the General Meeting [of royal commissioners], and the king (PRO ADM, 67/2; see Wren Society, VI, pp. 33-4). On 21 April 1696 the Fabric Committee approved 'A draught of alterations for making King Charles Building at Greenwich, with some Additional Building to be erected, capable of entertaining and lodging 350 disabled Seamen, with their necessary Attendants, which will amount to 400 persons on the whole', with a cost estimate of £15,250. The scheme was reported to the Grand Committee on the same day and approved, and ordered 'to be laid before Comissioners, and reported to the General Meeting on 24 April'. On 29 April King William III approved the scheme and gave it the royal warrant.

The 'Warrant design' drawings at the National Maritime Museum library (NMM ART 4/1-8; see Bold 2000, figs. 152-55; Wren Society, VI, pls 1-9) only show the conversion of King Charles II Building and the addition of a base wing. [5/1] is a partial plan of this scheme, the larger whole of which was ther 'three-block' scheme. [5/1] shows the hall as a detached range, with the colonnade in the near final position. The hall is the same distance from the King Charles II Building as in the earliest known complete plan of the three-block scheme. This is an undated block plan in the Lambeth Palace Library, drawn by Hawksmoor (MS 933/99; Bold 2000, fig. 140), and probably belonging to the latter part of 1698. In this scheme, the west ends of the hall and south dormitory ranges are linked to the central of the three parallel blocks by narrower intermediate blocks, each with a central passage.

Soon after he was created Clerk of Works on 22 July 1698, Hawksmoor began negotiating with the royal gardener Henry Wise for the purchase of a large plot of land west of the hall. On the Lambeth Palace plan this plot is marked 'Mr London and Mr Wise's Garden, called Blissett's Garden' ('Blissett' being the name of the previous owner, and 'London', George London, Wise's business partner). These negotiations were made possible by the increasingly favourable state of the accounts in mid-1698 onwards, when large sums of money from sixpence levies on seamen's wages began to come in. In the latter part of 1698, the three-block scheme was revised to a twin courtyard arrangement, named here as the revised executed scheme, [6]. The revision was complete by January 1699, when Hawksmoor was paid for a large, three-part model.

The elevation of the hall, [5/2], belongs to the three-block scheme, even though it does not have a dome. It is commensurate in scale, dimensions and detail to the two other known elevational designs for the hall ([6/2] and All Souls, Geraghty 2007, no. 201). In all three elevations the hall has been given a taller attic storey, to raise its cornice to the height of the attic cornice of the King Charles II Building.