Welcome to the great madness! Am taking bets on how long it will stay white but good for you! If I'm not covered in mud then it's tree pollen or bugs. But then I live in Vermont of the US of A and am subjected to far more insect life then those in Great Britain! This is so not fair...

What's your mileage? Who cares. Is it practical? See #1. What happens when it rains? You get wet.