PM Heathcote & RSU Heathcote 
AQA AS Level Computer Science 2nd edition 7516 [PDF ebook] 

This book is divided into six sections comprising 36 chapters, which together provide detailed coverage of the new AS course and the first year of the full A Level course. The specification is written in such a way that AS and A Level students can be taught together. All programming examples in the first two sections are written in pseudocode, leaving the choice of programming language up to the teacher.