I am very very suprised when I read your post Stanley!. Looks like we are one familly. Here what I know about my history.
I am living in Poland in Lower Silesia (dolnyslask, dolny¶l±sk), Boleslawiec (Boles³awiec). I'm Pole. All my family from father's side (as many other poles in 1945-1946) moved from jugoslavia (prnjavor) to Poland. Most of them settled in Czerna, Milikow, Boleslawiec. There is even bar near boleslawiec called "prnjavor" founded by people from jugoslavia.
My grandfather form father's side don't live anymore. He was born in jugoslavia and my grandfather's name was Adolf Plawiak. He is buried with his wife in Czerna.
There is now around few hundreds of Plawiak family members in Lower Silesia. Here you can see where in Poland are other Plawiak people.