I second Cadenza - it takes so long to get through the process! Where I am, practical tests are about a six week wait from booking, and the theory test was at least 2 or 3 weeks.
And don't forget working in lessons with your budget and schedule and your instructor's schedule. If you've got a good instructor, you'll find trying to fit in your schedule with his/hers will be even more difficult as they'll be booked up. It is worth the frustration, though, as a good instructor is worth their weight in gold.
I obtained my provisional in August, took my theory test in mid-September and started lessons shortly after. I just passed my practical this week (first try on all tests).
As to the question about a book to study from - yes, but I suggest getting the DVD/online program that will let you do practice theory questions straight from the DVLA. The questions in the program were on the test. And don't forget to get a practice program for the hazard perception test, you need to learn how to time yourself for clicking to spot the hazards.