I'm afraid this is a new one on me too, Moggie.
There are electric solenoid type valves that can be used to do the work of a stopcock, but I don't know what this is.
Googling doesn't return anything useful either.
Any fitting in the supply pipework could develop a fault and leak. In the absence of anything obvious, this must be where the problem lies.
Two more days of water running isn't going to do the floor much good. I'm surprised they don't have an emergency maintenance guy.