When was this? I was up in TVC (and later in that newer building up the road from it) in 1996 prototyping the BBC News Online publishing system with Fujitsu ICL. Didn't meet anyone from the Ceefax team though.
Which motivated me to work outside on the benches of the rather lovely walkway leading up to the building. Which in turn motivated me to write a pretty self-contained system. No Oracle databases for you! Was very beneficial for all :-)
The Ceefax team was in the next room, between us and the White City Bar.