Thank you all very much all so far. It's helpful to see the photos side by side.
I'm going to work through the hypothesis that they are Samuel BUCKOKE (1848-?) and Emmeline E DEASON (1850-1896), i.e. my Great Auntie Margaret's maternal grandparents.
Any thoughts on the below would be gratefully received!
Samuel Buckoke (born North Holloway, N London) and Emmeline Deason (born Stepney, E London) were married on 29 October 1871 in Shoreditch (E / NE London); they were aged around 23 and 21 respectively and both lived in roughly that area.
Samuel was a grocer at the time (having previously worked as a shoemaker), and the son of another Samuel Buckoke, a publican. Emmeline was the daughter of George Deason; he is listed as a clerk on the marriage certificate, but seemed to have a variety of jobs through his life (seaman, policeman, gatekeeper, labourer, and eventually ended up in a workhouse).
Could the photo of the couple have been taken around the time of their wedding, as a special occasion? They both look very dressed up. But to my (untrained) eyes, they seem older than 21 and 23 in the photo. I also wonder if it would be strange for them to have ventured to South London for the photographs, when they were based North East London - where surely there would have been photographers? Any thoughts?
Alternatively, in 1887 Samuel (age 39) and Emmeline (age 36) were living briefly in New Cross (South East London), at the time of the baptism of one of their daughters. Perhaps they had photos taken on that occasion? I feel like the couple in the photo could be those ages, although would it have been more usual to include their existing young children in the picture?
Samuel and Emmeline moved to a pub in Berkhamsted (Hertfordshire) fairly soon after - by the 1891 census; where Samuel remained a publican for many years (he had already been recorded as a beer retailer at some points during their London life). Could the photo of the man alone, taken in Berkhamsted, be dated around then or is it too late (estimates so far have been 1870s, 1880s)?
Many thanks,
Debs