I've cleaned many, many conservatory roofs without issue, however, I have a roof to clean that's an absolute mare. Its polycarbonate that's overhung by trees and the sheets are literally black. I've done it twice before. Once using a karcher pressure washer (I know), and once using a strong mix of virosol. Both times took me forever and my shoulders took a pounding. Neither times left a great finish, although the customer was happy. So what I'm wondering, is how would using hypo work out? Your opinions or ideas please on what mix or if its a bad idea.