Hello Stephen,
Your original question appears to have been answered, but if you are still wishing to trace the origins of your Great Grandfather may I suggest you do it from the English UK side. Try finding incoming passenger lists if he came as a refugee or emigrated. This should indicate where in Russia or Poland your relative came from, then tracing him could become difficult.
It sounds like he would have entered UK under his original name and then changed it as many did. Try the Archives at Kew for further information - naturlisation, etc. Do not give up.
Good luck
mj7777