ouch, I think it's reasonable to say I messed up in every possible way on this puzzle. I was rather tired when I composed it, someone else may want to have a shot. The idea was that everything obvious failed, including de5 because it would open up the pathway for the other rook, which I foolishly covered. Nxe5 was the idea. I apologise, I will look at my rubbish a bit more thoroughly next time.