Which type do you mean? The simple "Crown Over Knot" badge, worn during WW2 with both QVC and KC, and always in gilding metal, or the officers' pattern (which became the all ranks pattern in the 1950s)? They are not quite as hen's teeth as you might think, but prices vary hugely.
Crown over knot in white metal (except as collar badges) are dud as they are usually just South Staffordshire Regiment badges minus scroll.
