Really interesting nations opts and network chatter.

Interesting. The later map shows separate circuits from Manchester to Leeds, Newcastle and Glasgow. I wonder if that was done so Manchester could handle the SuperLeague Show without trying up additional circuits and having to staff a gallery in Newcastle?

I believe they did something similar when Plymouth and Southampton shared a political programme, they eventually fed Plymouth (or was it So'ton) from Bristol instead of from London. Then after all that effort cancelled the pan regional programme

I remember that political programme well. It was sent in the late 80s from Bristol to its own transmitters, as well as the line to Plymouth.
It was also fed from Bristol to London on a contribution and we opted the network feed to Rowridge to that.
Unfortunately getting the equalisation to match what Rowridge was expecting was never quite as easy as it ought to have been, and sometimes Rowridge would go over to its RBR of Hannington, forcing that to RBR CP.
So instead of the "South" programme the Southampton area got London instead.
Sorry this really has departed from a discussion about BBC Scotland.....

It's a fascinating discussion, I've asked the Mods to split it off to a new thread.

did Pacific Quay not have its own Teletext decoder, or am I misremembering? (I do recall occasionally having to reroute the input to CCA's decoder so that the correct channel number would appear on the top line)

Yep, that's exactly what I'm talking about. If my recollections are correct, the practice of using the BBC Two feed for this purpose had ceased by c. the autumn of 1983.

I need to sit down later and digest your other comments. This is good stuff. I appreciate the time taken to talk about this.

And yes, it'd probably be an idea for this to be separated out into a topic of its own: "Use of BBC Two distribution for programme transfers in the 1970s/80s".

I think the problem was Hannington's VBI indet reader (that read and validated the correct regional VBI ID, (part of the anti-hijacking system)) didn't like the distortion the ident suffered on its journey from Bristol, via London, via Southampton, via Rowridge, and then RBL to Hnanington.

Hannington rejected it, and went to RBS CP. I don't recall Rowridge going RBS Hannington, it stuck with the correct feed. I certainly recall Hannington showing London, and at the same time Rowridge on SO/BS.

It was a Sunday lunchtime, and I don't think there was any engineering effort at BBC Southampton that we could contact.
I had family in the Hannington area, so could easily check that the correct programme was on that transmitter.
Again the mists of time don't help the memory.....

Bruce Parker himself (who lived in Winchester and was a Hannington viewer) used to alert Bristol Comms
regarding the problem directly, I'm told !

Incidentally I've found a suggestion in an an ancient mailing list thread on this topic (which I think Mike himself started) that it was possible to switch a test card originating at Black Hill into the NI distribution at Carlisle.

I believe some transmitter sites could originate trade test sequences locally - could it be that rather than the regional centres opting out it was done at the TX site in some cases? Or did that end with the move to 625 lines?

Good spot. I raised this on MHP at the time I was pulling together that article for the site. I thought I got nowhere with this on MHP (I'm no longer on that list). However, had a look in my e-mail archive and one contributor supplied this:

"CP would have been fed TCF. Remember that the distribution was switched at LBH (Switching Centre). This had incoming feeds from Tel News, BH tv studio & Westminster and regions. Feeding any of these on the 'North' distribution would still have left 'real' BBC2 going to CP, South & West.

For Northern Ireland, the source of Test Card would depend on where the destination was. Assuming it was on the mainland, testcard could have been fed into the North distribution at Sutton (destination Midlands or East), or Manchester. I think that sometimes it originated at Shotts/Black Hill and fed to Carlisle BT and switched to the NI distribution. Of course if the destination was NI itself - I don't know."

While we're on this subject, they used to use the BBC1 distribution circuit during regional opt outs to feed stuff to the regions, often during the Friday opt for use in the Sunday Westminster programmes.

https://groups.google.com/d/msg/uk.tech.broadcast/lFP8_8y7_4U/ziNQMNImYZIJ

A blast from the past there.
I don't think it was a pre record, it was for a live interview on Look North.