Ask Italian have a great selection of gluten free dishes including Pasta, Pizza, Meat dishes, risotto and desserts. Their Chocolate Etna is to die for! Staff are knowledgable and food is good.
For our 1.5 week stay in London, I ate at this location twice and another location (Bayswater) once and never got sick. Their gf crust was actually really good. There is a dedicated gf menu. I only ever ordered the four cheese pizza so I can speak to anything else on the menu.
Amazing gluten free pizza and beer! Highly recommend