Thanks for your reply.
As I read those links, each of the relevant bodies requires you to take a specific (dance) teacher training course. It wouldn't matter if you'd passed every single (non-teaching) dance exam possible, starred in the Royal Ballet, partnered Michael Flatley in Riverdance, won the World Flamenco Dancing Championships and choreographed Cats. If you've not taken a teacher-training course, you can't qualify as a dance teacher.
If you tick the 'Teacher application pack' box here, and complete the form, BTDA will send you further details:
http://www.btda.org.uk/contact1.htm
For the BBO information, phone the number in my link above.
The RAD seems to only offer 'on campus' teacher training, with the exception of these two distance learning courses:
http://education.rad.org.uk/studybydistance
Chris