A watching brief was held during the digging of nine trenches in preparation for toilets and other structures at the open air market site in Vineyard Street. Five of the trenches extended to a depth of 0.5m and were either concreted or revealed nothing of significance when inspected. At the eastern end of the car park a trench was dug to a depth of 2.5m but its sections were largely obscured by shoring. In the southern part of the trench there appeared to be 0.5m of 19th/20th century brick above a deep layer of loamy sand with oyster shell, which continued beyond the base of the trench. The spoil heap contained Roman brick and tile fragments which appeared to be associated with this lower material. In the north-eastern part of the trench, clean sand, possibly natural, was noted at a depth of 1.85m. These deposits do not appear to represent the fill of the town ditch.<1>