there is a break in the circuit,could be 1,a local fuse supplying both bathrooms,fused spur in the loft, 2,junction box with a loose terminal that over time has shorted out and possibly burned away the conductor ie, like a rewirable fuse as per old fuse boards, mice say no more,if iv'e seen one crispy critter across a busbar iv'e seen a thousand.
sparkiefc, October 2009