If you had £2-3k to spend on a vocational training course/certificate/licence, what would you choose?

Depends what your skills and interests are, as well as what you’re physically capable of. I’m looking into midwifery for next autumn, if I’m healthy enough. There’s a dearth of midwives at the moment, so there are bursaries (not sure yet how much of your schooling they pay for, I haven’t  got that far in my research yet) and assuming you don’t totally blow it, it should be reasonably easy to find a job after you graduate unless something drastically changes (and for midwifery a drastic change would pretty much have to be a new agreement allowing more foreign healthcare workers; it’s not like people stop being born if the economy tanks). Plus it’s the kind of job that’s reasonably easy to transfer to other countries if you decide you want to emigrate. Pay seems to be kind of middling. Not great, but not the worst. If you don’t know what you’re interested in, it might help to write down what’s important to you in a career. To me, the important things are that I’m physically capable of it, that there are plenty of job vacancies, that there’s a possibility for emigration in future, that it’s not extremely dependent on the economy being good, that the pay allows me to support myself without needing roommates, that it allows me some degree of flexibility but also has regularish hours, and that the training isn’t terribly long (I’m 40, I don’t want anything where the training will take more than about 4 years, or I’d go back to medicine).