Hello Littlemum, how wonderful that your DS is inspired to take things further!
Without wishing to be the harbinger of doom I just want to add a cautionary note here before you go trailing all over the NW and end up with an hour's commute to a dancing school. Dancing is wonderful and fun and good for people in so very many ways BUT it can become a bit all-consuming. We went from a 1/2 hour ballet lesson once a week to dancing 5 times a week (1/2 hour ballet and tap classes, a 1 hour private lesson, a 2 hour troupe class and a conditioning class) AND his dance teacher still wanted him to do more. Admittedly a lot of this is because he dances in festivals and competitions but I just wanted to say, make sure your DS is happy at the school and that it's not going to mean you spend half your life travelling.
As well as curriculum it's worth finding out a bit about the character of the school. Some are very strict (almost regimented) with teachers who shout (and I have even known them poke [hit?] the kids with sticks!) others are more laid back with relaxed attitude to uniform etc. Your DS might get better training at the former but be happier at the latter - only you know your child. Mine both liked a stricter attitude - meant they got more done.
Other things to consider - do they enter festivals, put on shows and how often? As mentioned above it can get a bit much BUT - just doing exams can get a but dull and they can lose interest. Dance is, after all, a performance art - they should really get plenty of opportunities to perform.
I wish you the very best of luck with it all. My advice would be to find a good
local school where your DS will be happy. Let us know how you go on and if there is anything else you need to know
