Beautiful set indeed. Although bidders went crazy a little bit with the price in my opinion. I was bidding last year in one of the British auction houses 5 x RAF Poland titles (some even matching) and let it go at $380. Next time I can give it a shot and then we may split if you like. Bullion badge you can get easily below $450. Not small money, I know, but if it would complete my collection as a crown jewel I would probably go for it.
Or you can always shoot this "original" beauty from ebay, for only $577:
RAF WW11 Polish Officer Cap Badge with Real Gold Thread Genuine Very RARE Badge | eBay