Accepting that you have been kept busy at your workplace during the whole time the car was on the road, the fact remains that any vehicle parked on a road (whether it is taxed/insured or whatever) is, to all intents and purposes, likely to cause an obstruction to other road users. I think you may find that a notice will have been placed on the vehicle during some stage in which it was left on the road, which will have warned you of the consequences of action under the Civic Amenities Act, and so the Police/Local Highways Authority are perfectly entitled to remove the car in the event of your failure to remove it yourself. You are free to consult a Solicitor if you so wish in order to obtain advice on the matter, but I very much doubt that the law will be on your side in court.