New to Practice Management — what qualifications should I prioritise?

I've just been promoted from Deputy to PM at 31. My predecessor had an MBA and MIGPM. I want to invest in professional development but budget is limited (~£2,000/year from the practice). AMSPAR? IGPM accreditation? CMI Level 5? A healthcare management degree? I want something that's recognised and practically useful, not just letters after my name. What's given others the best return on time and money invested?