Saw a bloke cycling up a hill the other day with a front light on the rear of his bike. Pointed it out, he looked nonplussed. Hopefully he is not riding around any country lanes in the dark!
I always think reflective gear is better than hi viz. That and good lights as pointed out by all is good enough for a driver paying attention to see you. Disappointed to see the op say that oncoming drivers are trying to crowd them out, I cycle a fair few narrow roads and people are accommodating in general, certainly don't get people trying to squeeze me very often at all.