One practical moral to this story:
It isn’t smart to leave water in the pipes of an empty house where there’s even a remote possibility of sub-freezing temperatures. And it’s really, really dumb to leave mains water (or any other substantial source) connected to such pipes.
IOW:
Frozen pipes = bad
Frozen pipes through which much water can flow = unholy disaster
Note that in most cases the unholy disaster can be prevented by closing a single valve (takes about 10 seconds).
It is a bit dishonorable by the seller, especially since the insurance is going to pay for it, though I suppose they have a right to do this since the paperwork wasn’t completed in a rapid manner. But it’s an asshole move, and you are better off not trading with this kind of person, and thank your lucky stars this happened on their watch, not yours.
It’s in London, Shakespearo.
Is the house a “house” (as in, an independent building) or a flat? One of the reasons I have a housesitter is that my “house” is a flat and, even if I do close and empty the water pipes that service my flat, there are still other pipes in the walls which are not under my control, servicing the other flats. One of the times his pressence came in handy was when the neighbor below had a leak in one of her ceilings (that is, my floor): the problem came from one of her pipes, but the plumber thought he might have to open my floor (eventually he didn’t need to).