As a compositional student who knows how to play piano, the OC has magical power attracting me try to explore it. After listening it and doing some research, I have acknowledged that the score is available for sale on Sorabji Archive, but there are still rare performances.
Although I still haven't purchased the score, I am curious that if it is illegal or not to perform the piece, of course, as a student after purchasing it (Even if only purchasing its pdf). I am willing to pay the money as a respect to the composer, but I do not know if the copy available for purchase on Sorabji Archive is something giving you the right to perform it.
I noticed that Mr.Hinton is also in the forum. It might be a dumb question. I am looking forward to purchase and play the mythical OC.