Sutherland House was built in the early 1800's and is a Grade II listed building. It was purchased by the College in 1962 and used by the Research and Project division of the Physics department until 1984. I recall having a number of lectures / seminars there when I was doing a course module in micro-electronics. In 1984 it was used by the Drama department and then became the headquarters for the Drama and Theatre Studies department.
It was renamed Katharine Worth House and a new extension built to house the Caryl Churchill Theatre. I have no pictures for Sutherland House from the 65-85 period but in this picture you can see Sutherland House as the white building and (presumably) the brick built extension is the Caryl Church Theatre. The second picture is from Google Earth and that shows a further extension behind Sutherland House.