Slugs/bugs eating my Ludisia?

[NKOrchid]

Thanks for replying!
I guess it could be a lot of different things. I'm really hoping it isn't something that's alive. At the moment I'm keeping the plant away from the rest of my collection. Would using Physan 20 or a mix of water and alcohol help if it's slugs?
A part of me is also hoping that if it is snails, it's old damage and that the snails aren't there anymore... Which doesn't sound too likely to me.