I did 1 hour a week with an instructor (think I did 25 lessons in total, passed first time, did theory before I started lessons) but I also occasionally drove my now-car with my dad on learner's insurance so I did get a fair few hours in. If you do more a week you'll probably take less time to pass, but I also think having time to step away and process how to improve is good so doing more than 2 hours in one go might not be too useful and might just stress you out (I know it would me because I hated lessons, but now love driving myself). How many times a week you want to do a 1-2 hour lesson will be how much you can pay and if you can find an instructor who can accommodate the amount you want to do, I think most people tend to just do 1 session a week but if you are in the position to do more then I don't see the drawback.