Many of Malcolm Savilles books are out print now....I remember the lone pine series fondly...
Saucers Over the Moor; A Lone Pine Story by Malcolm Saville £70 - Jolly good 1950's fun with the Lone Pine Club. Redolent of Enid Blyton with much emphasis on location, these books include many vivid descriptions of English countryside, villages and towns.
The NEGLECTED MOUNTAIN by Malcolm Saville (A Lone Pine Story)
Mystery at Witchend by Malcolm Saville. His first book.
The Secret of the Gorge is No 11 in the Lone Pine series. A purchase by Jenny's father at a sale leads the crowd into another puzzle. This one is set some miles nearer to Ludlow, in the grounds of an old house, and there is the possibility that some jewels long since stolen may be hidden . . . the Lone Piners go camping in order to find out, but there are others on the same trail.