I will get the ball rolling,
I once pressure washed some ivy off a brick wall. It worked ok but at v high pressure, so i believe that pressure would work on tiles but im not so sure i would be comfortable using it on the job you show. It would need to be really water tight and the tiles secure. possibly a chemical and brushing approach would be better, sorry, i dont know which to suggest.
The only upvc cleaner i have used is thompsons, it works like t-cut. I used it to remove marker pen, hard work but effective.
i am sure someone will have a much better answer so dont panic, have you tried posting in the window cleaning section regarding the upvc?
steve