There were 15 W.E. Johns books issued in hardback format with a dust wrapper in the Hampton Library Series published by Brockhampton Press.
Six titles had been originally published by Oxford University Press, and the rest by Hodder and Stoughton or Brockhampton Press. Nine of the books were given a new dust wrapper design, with the rest having the same front panel design as the first editions. These books are commonly mistaken as first editions as they clearly state on the titles page First Published in 19XX, however they are all reprints and can easily be recognized by the logo on both the spine of the wrapper and the books (as shown further below).
Biggles Flies West was the first book in the series being issued in 1961 and the last title was Biggles at World's End in 1966. None of the titles are particular hard to find but in the last few years have become more popular as the prices are more reasonable compared to the first editions and the wrapper designs fairly attractive