Horseferry Road had a small studio when it opened, and was actively marketed for indies as '124 Facilities', so they are not banned from owning or operating studios.
Where did Right To Reply come from, as that was the only Channel 4 produced long form programme? Was there a small studio in the old original Hq in Charlotte Street?
Yes, a three camera studio, also used for in-vision continuity in the early years (mostly at closedown) . I went in it once, about the same size as the two BBC pres studios (that were used for weather, Whistle Test, Late Night Line Up etc)