Even if it does exist somewhere, I would imagine the tape has probably deteriorated greatly by now. Speaking of tape, it might be fun to guess what analog format it was recorded on. Probably U-Matic... or maybe Betacam?
Alchemy tapes were well restored for the bluray.
Yes, quality wise. But the person who decided to go 4:3 (on a Blu-ray for Christ sake!) should have been fired.
If it was taped that way it might be difficult to change it without compromising the image, who knows, I totally ignore about those tecnical things.
However, is not the same Channel Four who owns the Alchemy recordings?
I guess that if Universal / Virgin Records decides to release some day a special edition of Brothers In Arms, they could ask Channel Four for those Wembley recordings and release it on dvd, if they have the original recording without that awful analogic effects on the images, that probably were cool on 1985, but nowadays...