At nearly £2,000 plus air travel for just 6 weeks and to only get on the first rung it seems expensive to me. I'm sure I've come across these in the past at a lot less. Depends on class sizes, but if there's even just ten on the course they're making nearly £20,000 in 6 weeks
I doubt local wages or expenses are much, so that seems like a lot of potential profit.
Not really sure, but it doesn't look like a voluntary/placement, but rather just paying for a course in the same way as paying to go on a diving holiday to learn scuba. I'd much rather go on one that's run by charity and longer term to get some real experience rather than just a certificate.