I have just completed a timeline (with examples) for John Barnard (1841-1894) who took portrait photographs, and some views, when he had a studio in St Albans between about 1878 and his death in 1894. It seems he initially opened a studio in St Albans at the same time as he had a studio in Bedford. The St Albans studio then passed to another photographer, Atlas Church (biographical time line to follow), but when, after little more than one or two years, Atlas Church left, John returned to having a studio in St Albans. I am currently not certain whether the ""City Portrait Rooms" and the "Silvio House Studio" were in the same building or not.
Further examples of his work, particularly if dated or have a negative number, would be very welcome, as they would allow the time line to be refined further.
The picture of the lady "climbing over a style" comes from the City Portrait Rooms and dates from about 1880.