Hello,
I just found your post by chance today, and would be glad of a bit more detail, as I too have Hargreaves ancestors from Rawmarsh, albeit a bit earlier on, but there may be a connection. My great great grandfather William Hargreaves moved to Warren Vale, Rawmarsh about 1852 and died there in 1875. He was a manager for Charlesworths. My great grandfather Thomas Hargreaves was a coal miner and was killed in an accident at Warren Vale in Dec 1889.
I know from census returns etc. that there was another Hargreaves family living in the area, but have not found as yet any connection.