NB: The first two screenshots are of the first frame of a shot which are bad on both and awful on the R2UK, whilst the R2UK does have more print damage overall these frames aren't that indicative.
I reckon you're right and it's the R4 that has probably been "squished", but it's only by a tiny amount I think.
I would hope it's only a matter of time before someone gets this out on Blu-ray. I assume BFI still have the rights, wouldn't surprise me if they're waiting for Kadokawa to restore it.
Both the Ichikawas are severely under-represented on Blu-ray! I think there's something like a handful of Kon Ichikawa titles and none at all for Jun so far is there?