Don't pay up front and buy your own headset. Two key points. You'll fly better and learn more with a headset you are comfortable with. And no scrambling about looking for a club one before your lesson. It makes a big difference, and the instructor will thank you for it. I bought a passenger headset for £99 and it's wonderful.
I would encourage you to buy the books together if you can. There is overlap in some subjects and highly useful to have all the information at your fingertips. If speed is an issue, you'll be wanting to nail the exams as soon as possible, starting with Air Law.