On Monday 2nd Feb I made a report of dangerous potholes on http://www.fixmystreet.com and within 2 minutes it was notified to the Council.
Five minutes later I got an acknowledgment from the Council by email.
On Saturday 7th (most of) the potholes were fixed.
It turns out that once the Council are notified they are legally obliged to sort it out. Anyhoo - it worked for me.