The Radio City Tower has always used an all caps version of the type from the cog logo for its signage. Presumably because the signs for each letter would look odd in lowercase.
I always thought the sign at the top of the beacon was the logo they used prior to taking the generic-Bauer/EMAP one, ie the one they used in the mid to late 1990’s.
I've never come across any evidence of that logo existing. Supposedly the cog logo was introduced in 2000 which was when they moved into the tower, it always looked like an uppercase version of the same font to me.
I think you're right Phil. If Radio City's Logopedia Page
is to be believed (and admittedly it's not always that accurate), the previous logo to the cog used a very generic sans-serif font, as opposed to the rather stylised font that followed. It was all yellow text though, same as on the tower - so maybe that's where the confusion has arisen?
My guess is that they capitalised the text from the cog logo to make the sign more visible from a distance. It's clearly the same font.