Thanks so much for all your informed responses!(sorry, Ive only seen these now!)
Its a year on and Ive chosen not to go back to study and am filling every second outside of my FT job learning all aspects of motion graphics, its a bit of a hard slog, I feel like I have two jobs but im working hard on a showreel and I love it.
So thanks for your good advice, its encouraging to know that you can build upon all your work experience and change direction without retraining in academia.