The ITV broadcast is interesting - there's no burn marks, but there's different cropping, the color looks quite different, and it has the 1977 flyover (but the Episode IV crawl). It's obviously not from the same video master as the PAL video releases.

In fact, I bet that ITV didn't receive the film on tape. It looks like they were sent a pre-cropped, Academy-ratio, mono print and transferred it themselves, probably using a film chain hooked up to a VTR instead of an actual telecine. The blown-out contrast, blue-green cast and slightly yellowish highlights remind me of how movies looked on local (U.S.) TV stations in the 70s and early 80s, when they ran 16mm prints live on film chain.

My theory is that the version ITV got was originally prepared for airlines. There are airline prints of the films out there, and from what I can gather, airlines didn't show movies in widescreen. They were Academy-ratio, mono 16mm prints, so a cropped, mono print master had to have existed prior to the video releases.

This would also better explain why the Greedo subtitles on the old video releases are "burned in" and not video-generated - it makes more sense if they used an already-existing subtitled cropped element made for previous non-widescreen versions like airline prints (there aren't any Super 8 digests with the Greedo scene, are there?).

This would also explain the 1977 flyover - I'm assuming that the film element that was used for the ITV print didn't say "Episode IV," and the new crawl was tacked on for this version. (I'd love to watch the ITV version and see how it cuts from the Ep IV crawl to the '77 flyover...)