You most certainly do have grounds to make a claim, against the contractors, under there Public Liability Insurance.
Contact the council straight away, and report the incident, remember to get a report reference.
Get three independent Estimates and forward these together with a full report including Local, Time, damage coursed and how/what damaged your car. The council appoint the contractors and both the council and contractor have a "duty of care" to your property.
Don't sit on it, get on the case.