Teacher training is part online, part in-person.
It is very much not simply CPD. It is a new approach to training and assessing ballet learning, that Affiliate teachers may or may not decide to also run traditional exams alongside. While it is new to the UK, it is the way much of the rest of the (non-English heritage) world works, where centralised exams are rather less common. The new programme has similiarities with ABT's successful programme in the US in particular.
Here's a link to a chat I had with Mark Annear at the Royal Ballet School prior to today's announcement: https://www.seeingdance.com/royal-ballet-school-affiliate-training-and-assessment-programme-220124