That 'quite familiar' checkerboard signature dates back to 1988 and G-BOOV at Farnbough Air Show and appeared on virtually every UK police Aerospatiale/Eurocopter ever sold by 'DL' in the intervening years. Surprisingly it was not exactly common knowledge but he managed to slip it into most designs including POLA.
BOOV shed the checkerband when repainted into conspicuity but the point was that the majority left Oxford wearing it.
He designed that first ever UK police twin Squirrel paint scheme and decided that the checkerboard 'looked right' ..... drawn straight from the same design on his flat cap of yesteryear. The whole design was basically 'jam sandwich' police car.