In March 1977, the reconstruction of the floor of the sub-crypt ('small prison'), prior to its fitting out as a display area, offered an opportunity to obtain control data against which Laver's 1933 excavations (see ECC814) could be assessed. It also provided the possibility of obtaining some dating evidence from some of the strata, since Laver collected no pottery here. A six metre length of Laver's trench was emptied and two adjacent areas within the apse were excavated to provide dating evidence. The principal result was to provide additional data on the tile raft. <1>