London Gaunt Mystery Uniform Button 77 spade, gilt

Up for sale is this approximately 7/8 inch size uniform button with a des9ign that appears to be a reverse and forward 7 around a spade-like device. It is marked "Gaunt London" on the back and has heavy gold gilt on the front. The button is in good shape and may not have been used but does have a slight wear spot on the front. We have not been able to identify it.