If you know where he lives now, seek expert Legal advice towards a High Court Injunction, Costs against this antisocial neighbour.

We had a smilar thing years ago where we then lived.   It takes time, but failure to comply with the instructions in an Injunction amounts to Contempt of Court ; for which, Board and Lodging at her Majesty's expense, until the Court decides that the contemnor has purged his contempt.

Start, as has been suggested, at your CAB, with a view to being referred to the Duty Solicitor.