Sunglasses aren't a particularly good investment when there will only be a couple of weeks bright enough to want them :) But awareness of raincoat brands in Britain, now you're talking!
That's a good point; roads can certainly have a strong glare.
I see an independent optician who is fairly old. Although they sell sunglasses, the optician has never suggested that I should wear them. Do you think this is perhaps newer guidance that is shared by more recently-graduated opticians, or maybe something promoted by a major chain of opticians?