I did post a question before christmas about a good cleaner to use on upvc.
I did a gutter & fascia clean today & used "uPVC Cleaner" made by NILCO.
I found it brilliant as it removed all the black watermarks from the fascia with no effort at all.
Customer was well pleased.
Just thought i would post this if anyone else had a question relating to this or was having trouble with any cleaner they are already using.
Craig