Many thanks Garfield - yes, the mystery is solved! Apparently a long stretch of the road is on that one mains valve and it was indeed turned off for works on a property (my note must have been lost, didn't see any, but appreciate that the property owner made the effort and did try to tell people). The engineer did find that valve to be very old and rather prone to issues though when he did check, so in the long run, it may play up again for other reasons.

I shall wash my hair with Evian now instead, rumour has it that it worked well for Kim Basinger...