Driving lessons for teenager

[sillywoman]

We have a few teenagers who we would like to learn to drive. We don't have bottomless pockets (cos of the few teenagers) and would like a competent instructor who will put a plan in place with a rough time frame to get them through their test (we understand that this cannot be exact, but like some kind of rough plan). One of our teens has had some lessons with an instructor highly recommended on this forum but he's not particularly communicative with us, and seems content to just drift along taking our money indefinitely and so we would like to explore other options. Can anyone recommend good instructors for teens? How long does it usually take to get a teen to driving test-ready? Any constructive advice gratefully received....