It would totally depend on whether her current school is supportive of the arts. Do they allow time off to attend auditions, do they value the extra curricular as much as the academic etc? Does she feel she could set up her own extra curricular clubs if she sees a gap in the offering e.g. choreographing numbers for younger years. If it’s a struggle then I would consider moving her - school needs to be on board, not making it difficult. She also needs to be treated as an individual, not just a product of the school.
The thing is, unless she is at a specialist school, she is unlikely to progress or really gain very much from a move. Nobody in the world of performing arts is going to base offering you a job because you have GCSE dance or drama. It’s about how you perform in an audition - that one off chance on that very day.
I would recommend the holiday classes at Urdang. They do one for dance and one for audition technique. I also think the training and courses offered by the National Youth Music Theatre are excellent (audition entry), although concentrate on all of MT, not just dance.
She should take classes in as many diffferent genres as possible. Can she do Street / hip hop / popping and locking etc? She needs to be adaptable and able to pick up choreography in an instant. Attending classes with as many different teachers as possible so she is used to different ways of teaching. Head to Pineapple at a weekend and see what’s on offer. She should work also on strength, conditioning and stamina. Technique needs to be a given.
So you see, it’s all about working towards auditions. Be that entry at 16 to a college or for a job. Apart from having potentially a nicer time doing things she loves at school, a move doesn’t really help her on this path. Instead, fill every moment with different dance experiences, including watching live performances.
Hope that helps!!