Is this something you either want to create for yourself, or do on a voluntary basis, or is it a specific position you want to apply for?
If it's the latter then I'd forget the weekend/internet courses, there's more and more people doing TEFL/TESOL courses, it seems so higher and higher qualifications are being sought. I've seen entry-level positions requiring diplomas or even degrees in ESOL/EFL, the four week certificates are really the total minimum nowadays. Also something to note, if you haven't got a university degree getting on a four-week, no sleep ESOL/EFL course is very difficult.
But, if this is something informal, and what you're looking for is a knowledge base and some new skills, then the internet courses might be OK. You're likely to miss out on "hands-on" teaching, but hopefully you can find some willing victims to practise on.
I did the four week Cert EFL 12 years ago, and luckily it got me the job I wanted in France, where I very quickly learnt that four-weeks intensive course is only the tiniest tip of the iceberg when it comes to learning.
As for grants, no, I don't think they exist for ESOL/EFL training, but if this is a voluntary/charitable type thing, then what about trying some fundraising of your own. I'd sponsor you for sitting in a bath of jelly fixed to a sidecar chassis while being driven down the M1.
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