I am so sorry, I have only just realised I haven't replied! Alexander married Mary Brannie in Berwick upon Tweed and then moved to Hartlepool. In the 1851 census he was working as a dock labourer.
He died a few years later in 1854 in Stockton, Durham at the very young age of 29 leaving Mary pregnant with 2 young children to bring up alone. Thank you so very much for your link, it's fascinating.
