All things considered, it could be that the publishing of FotR might have began (or ended) on 29 July 1954, and the actual release date (when the books hit the stores) was 26 August.
Being a published author myself (albeit in magazines and quarterlies), the time between the two dates sounds about right for the normal gap between printing and distribution, and as the author, Tolkien wouldn’t have had to wait until the distribution date (if even to the end of the print run!) to get his author’s copies.
So maybe both the Daily News and Tolkien’s letters are correct, but from different points of view. I wonder if there’s any way to actually confirm if this suspicion of mine is correct, concerning this. The only ways I can think of would be to actually ask the Tolkien heirs (specifically his children) if they remember, or (an outside chance) if the Daily News and/or other English newspapers had a section on book release dates back in 1954, and someone could go back to the 5-week period in question’s papers (probably on microfiche) and look for the release date in them.
Great ideas! Any gumshoes out there up for the challenge? 🙂