Like numbers 8 and 9 (NPRNs 413636 and 423024) to the south and numbers 20?23 at the southern end of the square (NPRN 19375), number 6 and 7 likely demonstrate the original architectural design of Mount Stuart Square (NPRN 400316), built to the design of Alexander Roos, architect to the Bute Estate in c. 1858. Originally built as a domestic building, they were later converted for commercial use. In 1889, a wide passageway connecting Mount Stuart Square with Bute Street was added through the ground floor of number 7 and the entrance to number seven is now immediately within that passageway on the left.

The three-storey, single-bay buildings have rusticated ground floors with cornices above each storey, stucco facades, and slate roofs. The ground floor of number 6 has a segmental fanlight above the door and a square tripartite window to the right. Number seven has a modern two-light window with segmental glazing in the ground floor. The second storey has Venetian windows articulated by Doric pilasters with a stucco shell in the central arch. The third storey has shorter tripartite windows.

(Sources: Cadw Listed Buildings Database; Victorian Society Tour Notes, VS01/16)
A.N. Coward, RCAHMW, 05.07.2018)