Genealogical Query

I am researching my Polish heritage as my father was born in Rewa, Gdynia and lived their until the second world war. After the war he settled in UK which is where I live now. I know I still have some family connections there but am finding it difficult to make contact. I am mostly interested in obtaining a copy of his birth certificate as I am trying to obtain confirmation of citizenship. My two children also want to do this as they plan to spend time in Poland to gain a better understanding of their geneology. 1. Open