I have been going to Taste of Tandoor weekly for years. I am both gluten free and vegan, and the owner (Dave) is very helpful, as well are the other workers. You just might have to be a bit clear with what you are asking because there can be a language barrier with some of the servers.
There is a ton you can eat that is gluten-free. Papadam (lentil crackers), pakora (made with chickpea flour), most of the dishes.
Just stay away from the naan/roti/samosas.