Joshua Cooper registered his first mark on 17^th October 1786 as a buckle-maker.  He then entered a mark on 14^th September 1789 as a small-worker.  The “IC” maker’s marks are attributed to Joshua Cooper as there really is no other maker of this period.  The exception is John Carter II but he is identified as a specialist candle-stick maker and is shown to have only worked until 1777.  This therefore probably rules him out.