Have you checked: FreeBMD
There are a few Sadaski. Two in Leeds... your area of interest.
Then family or part of them seemed to have moved to Croydon, yes?
You might find links by checking those other people at freebmd.
Poland, Russia, Lithuania are all connected by 'Polish Partition'
If someone says he was Polish, but the documents say Russian. He was probably born in the old Polish territory.
There are posts about this problem in other threads.