this is inside one wall of the cloisters and is claimed to be the best preserved one in England. This is where the fully accredited monks who lived their lives within the monastry and priory washed; the dormitory where they slept was demolished when Henry VIII expropriated the monastries. The rooms where they copied and illuminated manuscripts is still there.
It is amazing that even in this space of such lowly use, the full grace of fan-vaulting was still used