memory of childrens book

[tibbsmcshep]

Any ideas as to the title or author of a book I read from 1950's or 60's set post war Channel Islands with visiting children searching for 'treasure' hidden from occupying forces. Clues included ormer shells and low tides.... not a lot to go on I know but any help would be greatfully received.

[Cetti]

Mystery on Rainbow Island by Dorothy Clewes.