St.Goerge’s Cross on a sheild enamel lapel pin Без бренда

St.Goerge’s Cross on a sheild enamel lapel pin.

I am not entirely sure what this pins meaning is. I know it’s comes from a deceased military pilots home in which there was TONS of military/flight stuff. Including pins. All I could find out is that it’s St George’s Cross. But the little M looking thing in the right hand corner stumps me and the rest of the internet.

Asking $9.99