oooo I don't like the sound of that. I doubt that bindweed is a plant that demands that sort of legal duty to remove. Maybe an ever so polite request to your council before they run out of money for weedkiller/employees to tidy up the mess might bring a result. I tried stuffing the stems in a plastic bottle and sraying weed killer into it. It knocked em back for a while, but alas they are back again.

if you spray then with a systemic weedkiller at the end of the summer they take it down into their winter storage organs. But keep pulling it out throughout the summer or you will be over run with it. You could ask the council when they will be next in your area spraying the verges and then ask them to do this area too.