Your Cassidys came to England before mine. I don't see any familiar names but I did look at some of these census records. Patrick was 7 years old in the 1861 census. That means he was born in Ireland in 1853-4. I found a Patrick Cassidy born in Derry to Daniel and Mary Cassidy on rootsireland.ie. If you purchased some credits, you may be able to find the maiden name of this Mary, the parish and perhaps address of this Daniel and Mary. They may be yours!