Retro CBBC question

The roof of TVC was last used in the summer of 1996 when they had that desert island set (which made it's debut in 1994 I think). Once they had the BP garden there was no real need to use the roof as they had their own outdoor area.

I remember during the Andi Peters era they would occasionely do CBBC on the roof in the afternoon in the summer, from some kind of quasi-broom cupboard set outside, to take advantage of the good weather.

On TMi there's a sketch which shows Sam and Mark running on a roof. Not sure abouts where abouts the roof is though.

The roof of TC4, as has been pointed out, was adjacent to the Presentation Studios and Network Control rooms at the time, and actually part of their fire escape route! It was therefore relatively easy to get cables and comms out there to do outside lives. TC4 was closer to Pres-B than Pres-A (CBBC's normal home) but the two studios shares apparatus rooms so it's possible they used some of B's facilities working into A for the Holidays on Two 'OB's.