My nephews course is £800 and included a day of off road lessons jsut before his birthday, then a week of driving 9-4, plus a theory test in the evening. He passed his theory test and his dirivng school get these short notice priority bookings for practical tests so will have a test about 10 days after his course finishes. if he fails then he gets free lessons with the same schoool until he passes, although I'm not sure if he has to pay for extra tests or not. But the thing is, if his driving instructor isn't very good, then getting free lessons won't be avery good thing if it takes him months. Plus he's starting back at 6th form soon so couldn't continue with it for long anyway.
If you're suited to that kind of learning then it can be worth it. Plus my nephews course is expensive, but it would work out cheaper to do it than standard lessons for some people.