Samuel was in the Dumfries militia which suggests he was from Dumfries not the Edinburgh area, Samuel Howatson born Terregles 1780 father Thomas.
There was a Samuel who was in the army born Dalkeith 1808 his marriage in Wigan in 1842 states his father Samuel was a soldier, his regiment took part in the riots in Preston.
James Howatson born Dumfries 1783 father Thomas, there was also a Thomas on the 1841 census who would have been James' son but he disappears after that.
James was 2nd bn north british dragoons who became the Scots greys, this regiment did nothing but fight at Waterloo, the fact Thomas was born c.1820 would suggest he survived the battle if he too part in it.
Jean Scot re married John Bishop in 1844 Bishop was army too, she wa sthe daughter of Robert Scot and Mary Swan, Robert worked the excise cutter The Royal Albert.