Your family is not Polish :-) They are Lithuanian from Suvalkija in the south-west of Lithuania. Your great-granfather was sent back to Russia, maybe Murmansk or Siberia, as a result of the Anglo-Russian Military Convention 1917.
My family are fromn Bellshill. My grandfather fought for the British and his brother chose to go back to Russia, but he ended up fighting for Lithuanian independence. I have lots of information and experience in researching Scottish Lithuanians.