It seems that vegan 'junk food' is more popular than vegan health food, and more places are opening each year offering vegan burgers and more.

Temple Of Camden is a firm favourite among vegans wanting vegan fried chicken. This is the sister cafe of Temple Of Hackney, but the Camden branch has indoor seating.
Located by Regents Canal, it is actually nearer to Kings Cross station than Camden Town.
Not only do they do vegan chicken products but also other seitan products including various burgers.
Definitely worth visiting.

What The Pitta's main speciality is a very tasty vegan doner.  Currently they have three locations in London - a cafe in Camden Town with a small indoor seating area, as well as outlets at the Boxparks in Shoreditch & Croydon (communal seating). They also have vegan Baklava on their menu.

​What The Pitta
​ https://whatthepitta.com/