This was long a bit of a grey area. It had traditionally been held that no new copyright is created by a facsimile reprint, since it is not a "work requiring skill".
Publishers of facsimile editions had argued that it was a "work requiring skill", since they didn't just blindly scan the pages from the original. Rather, they might also lighten the image if it's too dark to read easily, and might do some minor retouching. But the European Court ruled that this doesn't count as "intellectual creation", which led the Intellectual Property Office to state that "it seems unlikely that what is merely a retouched, digitised image of an older work can be considered as 'original'".
The word "unlikely" does leave a bit of wiggle room for a publisher to try and argue otherwise - but the sort of publisher who does these reprints probably hasn't got the money to pursue the matter very hard, and most solicitors would advise him not even to try since he probably wouldn't win in court.
So for practical purposes, we may take it that while new content (a preface, for instance) absolutely is subject to copyright, the copyright in the facsimile content expired when the original copyright did. Accordingly, any Bradshaws published on or before 31 Dec 1945 is now out of copyright.