Hi,
the 2-year MSc pre-reg is a Masters degree for students who have already completed a Bachelor programme but would like to "change' profession to become a Physio.
The MSc pre-reg Physio is therefore a baseline Physiotherapy degree. It is accelerated because the Bachelor degree that forms the basis of this Masters programme is considered to include elements similar to those being taught in Physio (e.g. BSc in Physiology). Not every Bachelor programme gives you entry for the MSc pre-reg Physio. And sometimes, there the Bachelor programme has to have occured in a certain period before starting the pre-reg programme (e.g. BSc must not be older than 5 years).

A general MSc Physio is a Master's programme for students who have already completed a BSc Physio - it serves the purpose of Specialisation, e.g. MSc in Musculoskeletal Physio or Neuro Physio or .....

Does this make it any clearer?
cheers,
Fyzzio