I used to live in Brighton, UK and it is extremely vegan friendly (and gay friendly and everything else friendly!). There are quite a few vegetarian restaurants, clothing and shoe shops. I didn't appreciate it fully when I lived there.
This is a bit O/T but I went out for dinner on Saturday night over here in France and we chose a pizzeria because Italian is normally pretty good for veg options. They had 3 'Vegetarian' pizzas on the menu, one which had tuna on it. I asked for a veg one without cheese...and it came with cheese on it anyway. They put mayo on my salad and butter on the garlic mushrooms -I had asked what they were cooked in and they said olive oil, but I could taste butter. Then I asked for 2 scoops of sorbet for pudding, one blackcurrant and one strawberry but they brought the blackcurrant with a dollop of regular strawberry ice-cream on top of it. Not a language issue -I am fluent in French. They just don't get it! I'll be interested to see if you find any vegan friendly towns in France.