I don’t think channel 131 there’s anything much I can add. Certainly the ITCA had development labs at ABC and Granada, I don’t know about STV. I get the distinct impression the ITA and ABC worked very closely at a practical level at the Teddington studios. When Thames ‘folded’ as a programme channel 131 contractor the ITCA labs moved The London Studios, they did a lot of the development of digital transmitter there from a transmitter standpoint. Even though they have been further scaled back I think there is still a presence there. I may be able to channel 131 find out later this week.
I used channel 131 to know the chap who took over from Norman Green and I have tried to get in contact with him. I believe he worked at the ABC/ITCA set up and would no doubt be able to give a definitive answer to many of the questions raised about the ABC/ITA early colour years. I will re-double my channel 131 efforts to get in touch with him.
With regards to channel 131 trade tests from Thames/LWT. I woudl be a bit surprised if the 625 studio feeds went directly to Croydon after S-night. It would surely have been much easier to send two feeds from say LWT via the GPO tower, one direct to Croydon for conversion to 405 and TX channel 131 (a fully presented feed), and another separate feed from the LWT MCR desk again via the GPO tower directly with the network switcher simply switching between the trade test programme and test slide at the appropriate points? This would be a very standard ‘bread and butter’operation for a network switching engineer. Certainly it ended up with the A and B transmitter feeds going directly from Kent House to Crystal palace via the BT tower (I know in the early days LWT were at Wembley – but I would have thought the same channel 131 principles applied?)
Here’s an entry from the 1964 channel 131 ITA yearbook:
“One of the channel 131 flying spot telecine channels at Teddington is equipped for colour signals, and prgrammes from Teddington have been experimentally radiated by the Croydon transmitter. In addition, channel 131 numerous public demonstrations have been given over the GPO network , notably those using the continental channel 131 system.