Does anyone know where I can find piano scores for Mogwai songs?

Find someone with musical training and experience who can transcribe the song for you. Be prepared to pay for it.

I’m convinced that if you can’t find something online, then it doesn’t exist. You could try to pick it out yourself, but that would require you to be a thousand more times talented than I. I don’t know, but I saw them once in a tiny little venue and they were so loud that it made me sick.