The very bottom picture shows an area of filler, that has been varnished, and if the varnish is the incorrect type, or the job hasn't been done properly in the first place, then the varnish will fade very quickly, its nothing to do with the window cleaner, the whole job to me looks like a bodge up, just look at the filler and the black mastic, it all looks like its been done by an Amateur, sorry Bonzer in my mind that is nothing to do with you.