Thanks for your questions!
1. Usually, the placement year happens the year before your final year (If you're doing a bachelors, year 3 out of 4.)
2. The fee is a flat fee of 1.8k (for now!)
3. You usually get paid for the year in industry- but that depends where you get your placement. I've seen it range from 13-50k. Mine is at the top end, as I'm at a bank. The average would be around 25k I'd say.
4. There is some intervention from uni (suggesting where to apply, help with CVs) but it comes down to you. I found mine basically alone.
5. If you can't find a placement, it's not a problem - you'll just be taken off the course with IP. The course I'm on actually didn't have an IP but since I found a placement they just changed my degree! If you can't find one they'll just put you on the integrated masters.
6. Yes, you always have to meet requirements to pass to the next year - usually just a pass. However, your placement provider (the company hiring you) MAY have a requirement (I have friends who need a 2.1 to be able to do the placement.) My placement didn't have a requirement, though!
Hope this answers your questions- feel free to ask any more!