As I expected, pieces of late Iron Age "local coarse ware" appeared at level 4.
Consistent with other finds in previous years, they are two abraded pieces of calcite-gritted pottery with a black fabric. Both are shown in the accompanying photograph. One has a buff/orange outer surface but on the reverse it is identically coloured to the other. The "grit" can just be seen as white specks in the upper sherd.
Although this type of pottery is a hand-made variety typical of the late Iron Age period it is highly likely that it continued to be made during the centuries following Romanisation, especially in rural areas and amongst the agricultural population.
The fact that such pieces of pottery are excessively worn at level 4 suggests that they remained in the cultivated upper levels of the soil after being discarded. By comparison, pieces found at lower levels are particularly crisp having rested where they were thrown without disturbance.