[JMT1985]

I’m sure this has been asked before, but was there ever a N4 or N5?

I know there was never an N7 to avoid confusion with TC7.

Yes, there was a N4 and N5 

N4 was converted into part of the BBC Club bar, and was not used much from what I was told 

N5 was used by the BBC Arabic service until they closed that studio in 1996. Sad that it was never used properly, in fact is was used for storage for many years, until the early 2000s, when BBC interactive took over part of that area to use for themselves

Yes, no N7 so not to confuse people with TC7 

BBC Television Centre was like a maze of studios, you could get lost in that building, especially the spur block, with the copious amount of offices in it, it was huge.