I can’t really see a problem, when said council/highways are doing said work at a reduced price you will be liable for these costs not your HA.
The HA if not already aware what Durham council/kerbo are doing in your area. Even if HA is to ignorant they could have far more easily than you got in touch with council who would at least brought your file up and told them everything there is to know about kerbo and their approval.
The charger is being fitted for free at no cost to the HA and will save them these costs in the near future when it becomes mandatory for HA’s
As usuall mr A. Hole at H. Hole HA is to enthralled in its on Bureaucracy, they fail to recognise a gift horse, even when its put under their nose.
Failing Mr A. Hole seeing sense I would certainly not let it lie!
I also hope Mr A Hole when he/she makes contact, he/she doesn’t think bricks will have to be removed to install a charger and a shade of red fitted in their place. Surely not I hear you say but its a dim witted HA after all ?