Gave the screen another really good do with the Bar Keepers Friend and it does seem to have shifted it, at least there isn't much hydrophobic beading going on now at least, however the wipers are still smearing, basically the wipers go over and leave a haze that evaporates after about 2 seconds.
I'm guessing some of the G1 is on the wiper blades! No idea how I am going to get it off them as they are brand new fitted spesifically with the G1, sounds like another £20 down the drain on top!