After a close inspection of my U.K. disc, I feel confident in saying there is definitely some weird digital stuff going on. I don't know if it's DNR or sharpening or regraining or what, but it doesn't look right to me.
The faces of the British soldiers look like wax figurines, lacking in fine detail. You can see the shadowing of their facial hair growth, but I'll be damned if I can see any actual stubble. Though I'll acknowledge this might be down to the make up they're wearing, but I've never seen anything similar in films of this era before.
What I can say for certain is digital though is the grain structure. Or more appropriately, the noise. It's definitely there, but is very fine, so to examine it you need to be up close to the screen. You can tell it isn't film "grain" because it all disappears if you pause the image. Once you resume it appears in select places of the screen, particularly around the white hats the British are wearing. As they move about, so too does the noise swarm and dance around the edges of their hats. Pause it and it simply vanishes. It's minute enough that I don't find it distracting at my usual seating distance from my 50 inch, but I can't imagine bearing it if I was using a projector.
Of course, the disc still looks "good", the colours are very nice and detail is far greater than I've ever seen on any DVD release. This is certainly no Spartacus, another Super Technirama 70 production. But I have trouble believing it is an accurate, film like rendering of an original early generation element. If the TT disc has real grain, even if it is larger than the noise here, I'll probably be replacing my U.K. disc.
One side note: how does one tell if a stereo track is "faux mono"? The track on this disc is definitely stereo, insofar that it has two independent directional channels. I don't know enough about how Zulu "should" sound, so what is it about the track that makes it poor?