Rhys, you are so funny. I hate slugs with a passion. Out here in British Columbia we get those giant banana slugs that practically chase you, but the normal garden kind are usually the black ones. In really cold winters, I stand outside imagining them all dying, however, as you know, that is sadly not the case.
My slug solution was to allow thick grasses and shrubs to grow around the boundaries of the garden where garter snakes can hide. They love to eat slugs. When my neighbour’s cat catches one, she brings it over and sets it free in my garden. I have not seen a slug now for over two years.