Im not a vegetarian myself, but... it looks easy enough. I mean, we have vegetables here (!!) and in the supermarket there are loads of vegetarian meat substitute things like Quorn, Linda McCartney, Cauldron, etc. And as someone else said, every restaurant menu has at least 1 veggie option.
There are several vegetarian restaurants in Glasgow, such as Mono, Grassroots Cafe, and the 13th Note. Plus, there are endless Indian restaurants, all of which offer many different veggie curry dishes.