The monument includes two moated enclosures located immediately to the north east and south west of St Andrew's Church, together with an associated area of medieval settlement between the two, directly to the north and west of the church.
The south western moated site includes a roughly rectangular island measuring up to 82m east to west by 60m north to south which has been terraced into the slope. This is enclosed by a partly waterfilled moat measuring an average of 14m wide and up to 3m in depth. A causeway across the north arm of the moat is known to have been in use before 1847 and is thought to represent the original access to the island. The southern part of the island is occupied by Brockley Hall, a Listed Building Grade I, which dates from the late 13th century.
The north eastern moated enclosure includes an island measuring up to 42m east to west by 24m north to south, which is enclosed by a waterfilled moat measuring an average of 7m wide and 1.5m deep. The northern arm of the moat extends westwards for 46m beyond the north west corner. A shallow bank, up to 6m wide, to the north of the north arm of the moat and the western extension, is thought to have been constructed with material upcast from the moat and forms a dam between the northern arm and the stream immediately to the north. A narrow leat links the north east corner of the moat to the stream.
An L-shaped area to the west of the north east moated enclosure and to the north east of St Andrew's Church, contains earthworks which are considered to mark remains of associated medieval settlement, and is therefore included in the scheduling.
The south western moat is thought to represent the site of Brockley Hall Manor which arose out of the estates of Peter and Alan de Brockley, held of the Abbot of St Edmunds, in the late 12th century. In 1286 the lordship was held of the abbey by John Algar for one knight's fee and encompassed `a messuage, 250 acres of land, 10 acres of wood, 8 acres of meadow and pasture, a windmill and the advowson of the church'. In 1302/3 Robert de Northwold settled the manor of Brockley on Alexander, son of Ralph de Walsham, and Joan his wife. Alexander de Walsham is recorded in 1316 as being `lord of the township of Brockley'. The north east moated enclosure is believed to represent the original site of the rectory and may be contemporary with both the south west moat and St Andrew's Church. Both moated enclosures have changed little since 1847 when they were depicted on the Tithe map of Brockley.
Brockley Hall, the modern garage, outhouses, sheds, walls, septic tank, steps and gates which stand within the south western moated site, along with the footbridge across the southern arm of the south western moat and all fences, tarmac and concrete surfaces are excluded from the scheduling, although the ground beneath these features is included.