Thanks for the message. Yes I posted the other messages and I did see the sale of the medals so sent the link to the Border Regiment Museum. Unfortunately the sale had passed but I think they sold for £800.
After my grandmother married my grandfather, their first child's birth certificate states mother's name as Reid, nee Jamieson, formerly Cameron. So we searched for a soldier called Cameron, with the MM, who died in 1918. Archie was the only one that came up. However, none of her later children mention Cameron and we can't find any marriages of a Jamieson to a Cameron in either England & Wales or Scotland around the appropriate dates. From the description on the back of the photo he was described as the eldest son of an old English Catholic family who died of wounds in 1918. Archie was clearly Scottish, and was the youngest of 9. My aunt (who wrote on the photo) was baptised at St Pancras Church in July 1918 and I was told her godmother was a Lady Joan someone, hence my aunt being given that name as her middle name. I suspect it would be more likely that the soldier was called John since their first child, born January 1916, was called John and that seems to have been the custom in the past to name children after the parents. One intriguing piece of information from Archie Cameron's service record is a Court of Inquiry report of him going AWOL in January 1916. A coincidence given the date of my uncle John's birth in January 1916??? Unfortunately I have been unable to find more information about this. It appears to have been cancelled from his record (a red line through the information) and he subsequently was promoted, so perhaps he had good reason to go missing for a couple of weeks?