There was a fader involved though as the cut to/from the commercial break was always done via a down-and-up, rather than the simple cut that most other regions employed.
You don’t need a physical fader to generate fades ! In fact probably 90% of fades etc you see on TV are not manually controlled via a physical fader
I accept that I had my terminology all wrong earlier; I thought a fader could refer to both the physical fader itself, and to the technology sitting behind it.
Still, it has led to an interesting side-conversation about mixing equipment, which I'm finding fascinating. That GVG 300 in particular is a stunningly-impressive piece of kit for the late 1970s, from the trade video on Youtube. That must have been state of the art at the time right?
State of the art and reassuringly expensive. The lower-spec GVG1600/1650 was a workhorse in many studios and OB trucks.
CDL mixers were also quite popular at the time. The BBC had a huge one in their large CMCCR OB truck (which itself had no cameras - it was used for combining the outputs from other trucks on major events) and BBC News was based around CDLs too. One nice feature of the CDL was that it had built in synchronisers/DVEs allowing you to cope with non-sync sources, 'freeze' a VT
before it ran out, and do shunts, slides, pushes etc. at the ME level (without having to use an out-board DVE) (I believe that was also an option on the GVG300 at one point)