As I've said before, my theory is that ITV transfer was sourced from a flat, cropped 16mm print, the kind that used to be screened on airlines before the video era.
Notice that there really isn't that much panning, if there's any at all; doing pans in the optical printer was time-intensive, so the operator usually used a fixed position for each shot. If they really needed to get from one side of the frame to the other, they would most often do a hard cut. Look at the first shot of the training remote scene, after Alderaan is destroyed. On most cropped transfers, there's a pan from Luke over to Ben, but in the ITV broadcast, it shows Luke training, then it just jump-cuts to other side of the screen to show Ben.
It can sometimes be quite jarring indeed - the old Video Treasures release of the Godzilla movie "Ghidrah, the Three-Headed Monster" used such a print. Someone would be walking across the frame, and the cropping would switch positions to keep up with them, causing them to seemingly "teleport" to the other side of the screen!
Anyway, if we could get our hands on one of those flat 16mm prints, we could see if the dissolve is there too. (They used to turn up on eBay from time to time.)
The transition between the '81 crawl and '77 flyover is also a dissolve. Perhaps both dissolves were on the print itself - but to answer that question, we'd have to find a flat 16mm that specifically has the ANH crawl.
In other news: In the "Tantive's Orange Items" thread, it was discovered that the 1994 French "Coffret Trilogie" release (the pre-THX release, aka the "Pyramid" box set) does in fact have the burn marks. ,,,^..^,,, had told me in a PM conversation that the burn marks weren't there, but he was obviously mistaken or didn't know what I meant.
That release also had the cloudless composite. It's interesting that every single official release, bootleg or print with the cloudless composite has the burn marks (or had to use DVNR to remove them). The 80s transfers without the burn marks all have the cloudy composite.
Now if only we could find out whether or not the Derann print has the burn marks...