Idk about the uk, but for personal experience it take around 3 days the first is for learning the rules the second day is going over them again and then doing practice tests and the third is only practice.
Update: i wasnt quite honest, i didnt really revise or learn anything till the day of my test (today) and i got 42/50 on multiple choice and 61/75 on hazard perception. I was literally exactly 1 mark off a pass smh (43/50.)