Tim the 1.75 should be masked from the full 1.37 open matte. SO sh9uld the 1.66 they've gone with for this. Hopefully they have, without cropping on sides.
Dave Mackenzie did the grading and encode. I trust him totally. HE described the impact of DV on the three strip re scan and registration for color as "insane".
Following a discussion on my FB page, people who know the record on Ealing and Aspect Ratios can confirm they jumped in early from 1954 for 1.66 as a masked ratio and DPs shot for that while protecting for 1.37. By 1955 When this was released they were shooting for 1.75 projection in the UK with...