Iain,
Failing that, have you tried Rain-X Anti Fog wipes?
Rain-X: Outsmart the Elements | Wiper Blades, Windshield Treatments, Weather, Bug and Tar repellent products for your car
A good wipe over on the inside before you line up on the grid usually does the trick. Used them in my TR7V8 to good effect. There always seemed to be unplugged holes in the floor (it wasn't seam welded) and steam from water splashing onto the exhausts was quite a problem on the screen. Rain-X 's other product, Water Repellent, works well on the outside too.
I remember on a tarmac rally, before I found Rain-X, doing a tight twisty stage with big drops into a gorge. My co driver and I decided we were safer going through the stage without seatbelts on so we could lean forward and wipe the screen rather than having the belts on and not being able to see where we were going! Hairy stuff! Fortunately conditions were that bad that officials couldn't see either! Thank God we found Rain-X soon after....
Cheers,
__________________
Russ
° Scratchbuild. Spaceframe Mk1 wide body. Dry sumped, forged, 351W. LSD930. 10's & 14's.
Most parts now sourced. Body 80% done. Chassis, rollcage 95% finished. Suspension 70% built. Engine starting to build, and trans in a million pieces.
http://www.gt40s.com/forum/gt40-buil...atchbuilt.html