James E Byrnes was a Midlands hotelier & restaurateur who came onto the 500 scene in 1952, racing a Mezzolitre. It isn't clear whether he was involved in the development of the cars in 1951, but by the start of 1952 he and Rupert Instone were racing regularly.
For production, the old Peerless Motors company of Slough was purchased, and it was decided to adopt this name, which still carried weight in the American market (and incidentally making it probably the first car to be named after a beer). Productionised with a fibreglass body, the Peerless GT proved very popular. Peter Jopp drove one to 4th in class at Le Mans in 1958, many of over 300 built were sold to America, and there was talk of dropping a Chevy Corvette motor in.
Peter Jopp at Le Mans, 1958
Unfortunately a falling out amongst the directors led to sales guru John Gordon leaving (he would later be half of Gordon-Keeble, a car that looks suspiciously like a Peerless with a Corvette engine) and soon Peerless went into liquidation. Renamed Warwick, the company stumbled on until 1962, but Jimmy Byrnes was now focussed on his restaurant and had little to do with the company.