I'm working on the William Babell Sonata II (from "XII Solos for a Violin or Hautboy"), published by Dolce. I'm wondering if there is a mistake in the score on the second movement, in measure 52. In every other measure where there is an accidental that affects the same note in different octaves, the accidental is written for that note in each octave. In measure 52, there is a high B natural on beat 1, then a low B without an accidental on beat 3. The movement seems to be centered around g minor, although there is only one flat in the key signature; it looks like there is a brief modulation to D major in measures 49-52 (sorry I'm a little rusty on my music theory). The figured bass shows a sustained G major chord in measures 51-52. My guess is that the low B is also supposed to be a B natural, but since accidentals are written out everywhere else, could Babell have meant for that note to be a Bb?
Since you are neither playing a Violin nor a Hautboy then I doubt Babell would be any more offended if you played the B natural that was surely intended. If a flat was intended then a cautionary flat would undoubtedly be included. That what I would do if I was playing it on my violin and your description is correct and I understand it correctly. There are even some people that would take inordinate pleasure from telling the publisher that they made a mistake. Hope that helps.