How do I connect a 1/2”BSP (F) Swivel inlet with a Quick Connect hose end?
Ok I figured out your sizes the gun takes a 1/2” BSPM thread 
Your link the male adapter 2.70 pound (your dollar? ) is the right one but there are 2 sizes FQCBM2 is a 1/2 BSP fitting so this should be the correct size.
I hope this gets you all set up it looks like it should from both descriptions.