The saga of our water bill is not yet complete.
First, we had one of their engineers round to check the meter on Friday. He confirmed that it was working and also that, because it did not entirely stop activity when the stopcock in our house was off, this suggested a leak. At the same time, we had another letter from Thames Water telling us that the reading that set this off was taken in early November and not September as the original letter suggested, scotching evidence of a huge disparity between a flood of water usage to September and then a tiny trickle thereafter.
However, he also suggested that, as soon as our neighbours were in, we performed a further test. On Saturday morning we turned off our stopcock again, opened up the inspection hatch and asked them to turn on the tap. The result was conclusive; the dial span wildly, proving that they are also running from the same metered supply.
The result is that our bill is now on hold and we are waiting for Thames Water to investigate just how many properties we are being billed for (they have had cases with eight or nine houses off a single meter, although two or three seems more likely in this case). Hopefully they will be able to fit a meter which is just for us as I am sure our frugal water ways should merit us a saving at the end of this rather scary tunnel of potential expenses.