Hi,
no regulations for massage - you can offer massages without registration; you are just not allowed to call yourself a Physio - not to your clients, not on business cards or advertising, etc..
Manual Therapy depends on the umbrella under which you were taught (I don't know the law, but am pretty sure), so if you were taught it as a Physio, you need to register as Physio, if you were taught as Osteopath, you need to register as Osteopath, etc.. As far as I am aware, manual therapy is a protected therapy and therefore underlies professional registration.
Other point is your clientele. Who would want to go to an unregistered Manual Therapist without professional liability and pay private fees when you can go next door to any registered Physio, Chiropractor, Osteopath etc.. and get it there for a fraction of the cost?
Good luck,
Fyzzio