I would go along with the general thread that Jeremy Pratt's PPL series is better than Trevor Thom, in that it is easier to read and has fewer mistakes in the Air Law section (as Angus Deyton says "Allegedly").
However, I would personally stay away from the PPL confuser as I am given to understand that it contains most of the actual CAA questions and model answers.
I think the exams are there to make sure that the stude has the minimum level of knowledge to enable them to aviate safely in the presence of others without killing themselves or endangering those around whilst they (and all of us) learn to become better pilots. If the stude studies for the ground exams with the phillosophy of learning 'parrot fashion' the questions and answers likely to come up so they can get the bit of paper, I don't know that I'd want to be in the same area of airspace as the person when they are in 'control' of the aircraft on their own.
Perhaps a better way of preparing for the ground exams is to use the questions at the end of the chapters in either Pratt or Thom along with the Question and Answer books that are available. There is one with cross references to Thom and a similar one for Pratt.
Good luck with the studying - I'm glad I don't have to do Air Law again (although on second thoughts maybe it would be worth a look to chide me into realising just how much I've forgotten!)