There is a screw on the corner of the guttering right behind your filter clamp but lower, it is holding the moulded rubber in place, I would be trying for a bracket from there to your clamp maybe cutting a slot in the rubber and getting better purchase off the metal gutter, hopefully stopping backward and maybe a little lift movement and if that doesn't work just slow down
The aerodynamics with the updraft from the windscreen and just the force pushing into the air at 85mph will certainly stress what normally wouldn't be. Largo's is just that little bit higher so the wind has a chance to release a little bit coming up off the windscreen and we will have to find out how it goes at that speed if he travels that quick, yours looks a little wider but the surface area would be much the same? How about weight?
