The small narrow garden of the premises was known to overly the portico of the Roman temple precinct, first located on the adjacent site of nos 77-9 Castle Street, now St James' House, in 1976 (Arch. Cant. xcii (1976), 238-40). Amongst many discoveries during the earlier excavation was an intact row of stylobate blocks for the colonnade supporting the pitched roof of the portico, this revealed in a small trench against the party wall separating the two sites. The 1976 excavations also provided important Early Anglo-Saxon finds in dark earth deposits overlying the old Roman portico and courtyard surfacings; these included the remains of a sunken-featured Anglo-Saxon building, which re-used fragments of a Corinthian capital as chock-stones in one of its load-bearing post settings. The excavation at no. 76 Castle Street was undertaken in the hope that further portico stylobate blocks would be revealed under early Anglo-Saxon dark earth deposits.

The excavation, funded by Mr Colin Tomlin, the owner of the property, commenced with machine removal of garden soils that had accumulated over a considerable period. Several post-medieval rubbish and latrine pits were found to have cut earlier levels: these included a large brick-built soakaway located against the rear perimeter wall of the garden. A number of medieval features, mainly pits, were also encountered. The earliest of these, a wide linear slot extending across the excavation on a north-east to south-west axis, dating from the mid twelfth century, proved to be a robber trench for the Roman stylobate. Large fragments of greensand blocks and tip lines of mortar from stylobate masonry were noted in the soft backfill of the robber trench.

Overlying the final late Roman courtyard surface was a 15 cm. thick deposit of dark loam, which yielded a small corpus of sixth-century potsherds and an early Anglo-Saxon copper alloy brooch. The matrix of the dark loam contained considerable quantities of Roman building debris, including patches of compact gravel and fragmented tile, perhaps, indicating the presence of rough surfacing associated with the structure, located nearby in 1976. A large number of late Roman coins were retrieved from within and under this dark earth horizon, their frequency increasing as the latest Roman courtyard was uncovered.

The latest Roman courtyard, of flints, pebbles, crushed tile and brick, crushed waste mortar and greensand and limestone lumps extended over the greater part of the trench. Worn areas in the compact pea-gritted horizon appeared to indicate that disturbance may have occurred during the formation of dark earths after the metalling. This phenomenon noticed during earlier episodes of excavation in the temple precinct (Arch. Cant. xciv (1978), 275-77) may relate to an early phase Anglo-Saxon occupation, when the southern corner of the temple enclosure was utilised for some form of agricultural activity, perhaps the penning of animals.

The latest Roman courtyard extended as a continuous horizon across the earlier portico position, broken only by the robber trench of the stylobate. In earlier excavations it had been clearly demonstrated that the portico had been demolished and its paving stripped prior to the laying of the final courtyard. Coin evidence from earlier excavations indicated that demolition may have taken place in c. A.D. 350-60, but no datable finds were recovered from the present excavation to confirm this. A well-defined linear depression in the final courtyard surface against the north-west side of the stylobate robber trench proved to be subsidence into the backfill of a late Roman robber trench for the stylobate drain. Fragments of greensand recovered from the fill of the robber strongly suggested that the drain was of stone designed to take water from the portico roof.

A sequence of three well-defined courtyard metallings was excavated west of the portico, the earliest containing a high percentage of greensand and limestone chippings in its matrix. Deposits of poured mortar and clay under the final metallings in the portico appeared to be the disturbed remnants of construction and bedding deposits for a possible stone pavement.

The early courtyards and associated deposits were remarkably void of finds. Earlier excavations were equally remarkable for the paucity of dating evidence. Collectively however, the small group of datable finds from earlier episodes of excavation suggests a construction date for the temple precinct of c. A.D. 100-120.