The Sumac Centre is a campaigning social centre with a vegan cafe and bar run by volunteers. As it is registered as a Social Club, you have to be a member to be there during licensed hours, though it is easy to get someone to sign you in as a guest. The opening hours are limited and subject to availability of volunteers, so check beforehand.
Food service is currently limited due to a lack of volunteers (why not help?). There are sometimes evening meals and breakfasts available.