Anne Digby 
Unforgettable Fifth at Trebizon [EPUB ebook] 

The end of the GCSE year looks set to be unforgettable as the six friends plan the return visit of their French pen friends. But in a term already full of dramatic happenings, nothing could be stranger than the way Emmanuelle behaves and Rebecca is devastated until she finds out why. She also gets her GCSE results at last and resolves the Robbie v. Cliff dilemma, thus bringing this classic series to a memorable conclusion.