Level 2 Skate UK Coach cert qualifies you to teach group classes of the Skate UK levels. You can't coach independently and can't get paid. I need to have a chat with NISA/BIS about my qualifications so I'll ask them to clarify the test pass requirement for each level.
One thing I would say is that higher level test passes are still no guarantee of high quality coaching, especially of basics. It's the quality of the coaching that the coach themselves has had that makes the difference. Basics are everything, but many coaches want to get to teaching elements too quickly. I see this especially with younger coaches. Teaching is often finding 50 different ways to convey the same information, sometimes more. Patience and a sound grasp of the mechanics of skating areas vital, as are the communication skills to explain why things happen/work/don't work...