Okay, we can all breathe again. I've just received that email ... which included possibly the last letter received from Duncan John Tatham. It seems DJT took off - as suspected, having inherited some money from his Uncle Duncan Dunbar's estate (and also from his Tatham half-uncle) - to do some hunting in America. The letter mentions hunting, and comments on the possibilities of getting scalped by the Sioux (

), or shot by someone in the event of any disagreement!
Unfortunately, it appears to me that the letter was written well before the 1880 US Census which put DJT in Laramie City.
However the email also mentions that the gravestone for Justina Tatham (died 1870) refers to her father as 'the late Duncan Dunbar Tatham'. Justina died at Hatfield, Herts., ... anyone feel like wandering around the cemeteries around there?
Will update everyone if I hear more!
Deb