This has been a nightmare to track back! He is married on the 1851 census, but have not been able to find any details at all on them before that census. There is an older family of Greenwood's on the 1851 census that are also anchorsmith's and I'm assuming could have been his Dad as he is right generation, but can't find marriage or birth records for him (they were in Hough Green then). It's possible the family were still in Liverpool in 1841, but I've drawn a blank on that census too!