Yeah, I don't see why 3 one hour lessons would be bad if you have the time and your instructor has the time to book you in. In terms of being ready for your driving test, it really depends on how you take information and how you progress with your lessons. Some learners progress slower than others. You have to see for yourself how fast you progress and then you can change your driving lessons per week, if instructor allows you to.
My sister has purchased the whole book pack for her theory test, so I used that. I went through 'The official DSA Theory Test for Car Drivers' book, 'Know your traffic signs' book, 'The official highway code' book and also looked into the 'The official DSA guide to driving - the essential skills' book to cover up any things that were not taught in other books. I passed my theory first time with 50/50 on multiple choice questions.
Good luck.