[Gav]

Hi Chris,
I used to have loads of under bonnet pressure before I fitted alloy flashings around the radiator.
At speed the bonnet would lift half way up the windscreen if the catches weren't properly locked, now it doesn't lift at all with the latches undone.
So...
One could assume that without the flashings in place the air would be going out the scoop.
So I'd get that done first and your radiator will work better too.

Gav