Loos?

The "Monk's Lavatory" is a long shared basin that would have been used with fresh water flowing along the trough.

If you look carefully you may be able to see the multiple sink outlets.

I just love the intricate detailing in the ceiling throughout the cloisters of the cathedral. This was a terrible photo as I took it when the camera was wobbling all over the place (trying to carry too many things). I think I have just about rescued it by making it black and white and then turning up the contrast a little.