GrumpyGregry
Here for rides.
I have been using a helmet/eyeglasses mirror for 35 years. I don't know if it's "cool" but I really don't care! Only a KID worries about looking cool when SAFETY is involved. A mature person is beyond that. I won't say that the helmet/eyeglasses mirror is the best, but after trying various bike-mounted mirrors, I think it works the best for me. I like being able to "sweep" behind by turning my head slightly. It takes a little practice to get used to, but once you get used to it, you'll find yourself looking for that mirror, even when walking on the pavement! LOL NOW...I'm coming to visit the UK for a few days, and hope I can find one for your side of the road!
enjoy your trip to London threefingerjoe. Should take you about 15 minutes to work out, once there, that the only thing that matters in the London cycling scene is how cool you look. The streets are infest with a plague of tragic hipsters.