Evaluation by J Payne of SCAU did not reveal any features of archaeological interest although a probable Mesolithic, edge-modified blade and a rim sherd fragment of medieval pottery were recorded.
Surrey County Archaeological Unit
Watching brief by M Saywood of SCAU revealed no finds or features of archaeological interest.
A test pit evaluation by W Weller of SCAU showed limited potential, with the only finds from the topsoil and subsoil. No archaeological features were revealed and most of the artefacts were of post-medieval date.
Watching brief by M Saywood of SCAU indicated that the ground had been previously levelled. A small area of earlier exterior ground surface was revealed, with remains indicating a path or drainage feature that dated to the post-medieval period.
Two phases of evaluation by M Saywood of SCAU, following the demolition of Garrod House, exposed considerable modern truncation. No finds or features of archaeological interest were revealed.
Evaluation by M Saywood of SCAU recorded no finds or features of archaeological interest.
Watching brief by W Weller and M Saywood of SCAU during ground level reductions for the installation of an anaerobic digestion facility revealed that the area was deeply disturbed, with made-ground comprising large amounts of 20th century waste. No finds or features of archaeological interest were revealed.
Watching brief by W Weller of SCAU conducted in 2016 during the replacement of the school swimming pool building and within the boundary of the Scheduled Monument, failed to expose the archaeological horizon. No finds or features of archaeological interest were revealed.
Strip, map and record excavation by T Collie of SCAU, undertaken in 2016, revealed a complex, Middle–Late Bronze Age/Early Iron Age system of ditches across the east of the site. Oriented north–south/east–west and in places formed of a double ditch, it extended to the centre of the site, where the principal ditch turned west towards the river Ash. The ditches may represent a domestic enclosure, although their generally shallow nature suggests they form part of the wider Bronze Age field system known to extend across a large area of the river Thames gravels both north and south of the river.
Watching Brief by M Saywood of SCAU revealed no archaeological features or finds pre-dating the 19th century.