[Stooky Bill]

From what I remember, Radio 1 used the secondary audio channels of (UK) Living.  BBC stations from what I recall used Flextech channels to stream their channels.

Yes, they used UK Gold and UK Livings audio subcarriers, those being the neareest the BBC had to satellite services in the analogue days. 

Radio 1 and 2 were stereo on one and the rest mono on the other (a stereo service taking up the equivalent of two monos). 

A lot of British channels had radio sub carriers, which were intended for language options (used by Eurosport and Euronews) IIRC Virgin was carried on Sky News 

The other notable station was Sunrise Radio. This was the London Sunrise station and was used by some radio stations (particularly RSL licenses) for their feed of IRN. The satellite feed muted for a couple of seconds before and after each bulletin so anyone taking it didn't get a snatch of their jingles.