 But although Blacket used the paired windows at St Philip's, the design was not a replica.Blacket was masterly at designing in the Perpendicular style and, as with other designs (such as the spire of St Mark's), he produced alternative versions which he slotted into place on the drawing or glued on as flaps, so that the Parish Council could choose.In this case they selected a design with double the usual number of windows in the clerestory level, and also two large windows in the southern side of the chancel as well as the six-light window in the eastern end, so this church, in contrast to St Paul's, Redfern, is unusually light.