Yes, I think the Grade A training provides graduates with a relevent postgraduate qualification e.g. M.Sc in Medical Physics and training under supervision. At the end of this the trainee will have been assessed for competence by exam and assessment I think. Training and assessment is done by placements within relevent departments. A candidate completing the grade A training is eligible to apply for grade B posts and then progress through the system.
The infrastructure is there in Regional Medical Physics Departments, to some extent, for the Clinical Scientists training and I suppose this could be expanded to Clinical Technologist training.
What I was getting at about extending the training to Clinical Technologists is that the Clinical Scientists could help provide the academic stuff and are usually involved in the provision of Medical Physics equipment maintenance (including Radiotherapy and Diagnostic X-Ray) and have links with Universities and other departments. They are set up, in some respects, to branch out into training, or at least the organisation of Technologist training, by Technologists, in their departments. Certainly for 'Physics' Technologists anyhow.