Thank you for the extra info, it's really helpful! I'll go have a look and unpick it all - I'm now wondering if there could be two Joseph Carnalls of the same age married to Mary's in the area?! Seems so very unlikely but in the Mary Warrilow marriage he lists himself as bachelor which is curious - that plus no death record for the original Mary.
The child I'm interested in is the James born 1815 so he definitely seems a Hollins child at any rate but I hope I have the right Joseph.
Thank you everyone, really appreciate the help!