Thanks Jez G and Whirlygig. Your responses have proven extremely useful. A school teacher was recently talking about the differences between UK and US approaches to learning. The one thing I picked up is that the US system, focuses on what you actually need to know and tends to be more specific. In the UK, it tends to be 'learn as much as you can and we will test you on some areas but not all'. Books in the UK are often 4 to 5 times thicker than US ones.
If the JAA syllabus is so important, I am at a loss to understand why only certain areas are tested. Call me cynical but one might say that the JAA & their ATPL providers are creating a very lucrative industry. Certainly top UK pilots I have spoken to believe that much of the ATPL ground-school syllabus is irrelevant.