As with all intensive driving schools, your experience will be entirely up to the instructor you get. I HIGHLY recommend using their free driving assessment to your advantage, so you can meet your instructor, see how many hours you need etc. Organising dates and sorting test times in the COVID era are an absolute nightmare, and so be sure you can be flexible with other commitments since you don't really get any say in these - the test will be booked, and you'll be told when it is. The lessons, however, are almost entirely up to the instructor. In my experience (living in Aylesbury), I had Catherine teach me from being fairly inexperienced (about 5 hours into driving), up to a competent state within a couple of weeks, using up some of my hours. The week before my test (today), we used the final 20 hours, and polished everything to where it needed to be. For someone like me, who needs to just experiment and learn practically, Catherine was incredibly patient and knowledgeable. Today I passed with 4 minors, on my first test. TLDR: Momentum are perfectly okay as an agency. They'll reply to your emails, and sort things out within reason. It just happened that the instructor they had for me couldn't have been better. 4 stars seems fair.