I lapped up everything Biggles when I was ten years old but seemed to have missed this one, so thought it would be good idea to fill in one of the gaps.
The First World War stories were always the best - they were more involving, more plausible and our hero felt a little more fallible. This was true even of Biggles and the Rescue Flight, which was written at the same time as Biggles in Spain.
Bearing in mind that this was when Captain Johns was favouring a less subtle style to gee up patriotic schoolboys, we can perhaps shrug off the odd stereotype or over simplistic viewpoint, because the best of Biggles' and his time is still always there.
The action and plotting are as crisp as ever, of course. Not the best but still a swift and energetic read.