I guess the suggestions I've made are what I'd personally go for, partly out of a secret life long hatred to always defeat all bloody minded, self-centred mechanical things in general, and partly out of curiosity to solve the heat problem once and for all [
] Anyway final thought on the matter which I'd also go for on top as a final back-up....
Instead of the existing double action (?) bonnet lock fit a new interior lever operated mechanical spring loaded one instead, that however will also permit several different
lockable bonnet opening heights as well depending on how urgent the need is to remove excess heat build up. Then when all the temperatures are back to normal whether stationary or driving close the interior bonnet lever.
Possibly avoiding the odd penalty point into the bargain too ! [
]
Good luck whatever you decide
Cass