When you write to the council - and well done for doing so - who not mention that given their past unresponsiveness and your strong conviction that every moment's delay represents a very real risk to people's lives, if they don't get back to you with a reasonable response within, say, a week, you will send a copy of the letter and a brief summary of the background, to the makers of Top Gear. And if they don't, do.
They're always on the lookout for good 'issues' to cover, and may well be interested in doing a feature on who exactly is responsible for taking appropriate measures to safeguard people using the roads. I doubt anyone at the council would be keen to even risk being flagged up on national tv as having ignored repeated warnings and five accidents, one fatal, and failed to provide a safe environment for the public at large.