Looking at newspaper references, Alexander Lawrence (photographer at 80 Queen Street) died on 31 December 1894.
As mentioned by Hanes Teulu, J Lawrence is reported as a photographer at that address in various papers in August 1895. "A very perfect photograph of the principal officers who were present in the service on Friday connected with the hanging of the old Crimean colours has been taken by Mr J. Lawrence, of 80, Queen-street, Cardiff"
John Lawrence had moved to St John's Square by August 1899 "At a convenient moment the whole party were photographed under the Castle walls by Mr John Lawrence, of St. John's-square, Cardiff"
So this photo dates from that 1895-1899 period.