Sadly the technology (as in a video link to the UK) did not exist at the time, so the only option would have been for CTV to establish a playout centre in the UK. Therefore any concepts of CTV networking the UK are really a hypothetical possibility more so than an idea that ran through the minds of most managers at CTV, unless one knows otherwise. I don't think that the number of staff at CTV had much bearing on the issue though if the IBA handles matters once the feed reaches the UK.
The ITV strike is notable as the first (significant) instance where the unions and the working classes crossed paths with each other. ITV was preferred by the C2, D, and E socioeconomic groups whereas the BBC was preferred by the A, B, and C1 socioeconomic groups. It's unclear how well the unions realised this.
Was there any detailed contingency plan ever put in place by the IBA to deal with service provision during instances of large scale industrial action at programme contractors?
The information that you have provided about the network feed passing through the MCR of the local ITV studio on its way to the transmitter is probably the best and most compelling answer as to why CTV (if it actually had a video link to the UK) would be unlikely to network their programmes and provide a minimal service. If the MCR rooms are out of action then the feed cannot progress from the GPO network to the transmitters unless the IBA installs a bypass network.
This does raise ethical questions whether an ITV programme contractor should or should not have been allowed to block ANY networked programmes from its transmitters as a result of strike action or otherwise...
As an engineer rather than someone who has the management or political control, there are a few things that come to mind here.
Firstly, the assumption that because ITV was watched by the working classes, the unions would not have wanted to affect it.
I grew up with the power going off in 1973, and that affected us, not just those with money to burn, although it may have kept them warmer. Strike action affected everybody.
Secondly, why would the IBA have financed a back up system to allow anything to keep programmes on the transmitter network? It would have been so unlikley to be used, and have cost a fortune to implement. With hindsight you can say that it could have been used for 11 weeks in 1979, but who knew that would have been the case then?
Thirdly, the question as to should the ITV contractor be able to block anything going to air that wasn't from their station, well, that is quite a question it is not a technical one, but a political one that has to consider where the consent to have the right to air material came from.
The IBA were the broadcaster for ITV, and could have broadcast anything they chose. They chose not to.
Why?
Consider what that would have done to the whole Independent Broadcasting system.
The contractors would have been up in arms, not just the unions, but the management.
There would have been support for this across a wider part of the media and communications industry not just broadcasting who would have been concerned about editorial control and possible censorship.
It really is so difficult to explain now why this would have been such an impossible thing for the IBA to do.
The UK was in a different mind set.
I don't remember thinking - I wish Channel TV would supply a load of repeat programmes to keep something on air.
I just thought ATV is still off.
It was what it was.
Does that seem odd?