Somewhat indirect but:
BNA has the Hexham Courant from 1864-1897. The first advertisement for T H McAllan, music seller, appears in 1877. It refers to a large stock of photographic albums, but not to photography.
There are adverts throughout 1879 referring to "Portrait Rooms Open Daily". Also refer to having been established 18 years.
Then there is a long gap until 1889 when there are adverts throughout, but these don't refer to the Portrait Rooms.