I'd be extremely cautious too, coke - it doesn't add up. Nobody would put all their vital papers in left luggage, you'd carry those with you, you never know when you might need to produce them. I'd say it's a scam - and it's very easy to be taken in by highly credible people. If they make an exception for her, they'd have to do it for everyone. It's doesn't ring true at all to me. How come she knows where and how to contact you? I'd be very careful indeed.
Just say you'd fallen for it, being a kind person, and given her £200 - how would you get your money back? The odds are you wouldn't. I wouldn't get involved, it's not your problem.