Hadn't thought of checking to be honest, might be worth a call. But there's no damage anywhere! ... I've googled and found people who are 'leak detectors', will give one a call on Monday.
This might be a daft question, but you aren't in a terrace are you? The toilet and shower for one of my neighbours is still on the shared supply through back garden, even though they have a new meter out the front.
It is possible, if the fill tap is open but either it would be leaking or pissing out of somewhere under pressure.
Sorry, shit situation. Covered for this on insurance?