With a combination of a flocked brush for added scrubbing power and plenty of Virosol (spelling?) as an emulsifying agent, I'm still battling my way through my round as a consequence of all the gritty grease deposited on the glass by the storms.
95% of the windows in my area (Horley, Redhill, Reigate) have been effected to some degree, a fact that isn't overtly obvious from the outside, unless the sun shines on the glass at a particular angle.
Anyone else struggling?