One must admire efforts to maintain business premises in as an attractive condition as possible, but painting black mathematical tiles seems to be going a bit far. Wouldn't a good washdown have sufficed?
The Pump House in Brighton Place is named for the town well which once stood in this area near the very centre of the old town. The mathematical tiles were added, to an 18th century (or earlier) building, in the early eighteen hundreds.
Part of the rear of the building is said to incorporate sections of a very thick wall of a very early date; possibly from the same era as the priory chapel which once stood nearby in Bartholomews, although this has never been reliably confirmed.
Plaque on the wall of the Town Hall in Bartholomews.