If you’re just referring to the restaurants, I’d just call one of those restaurants an Indian (as in the cuisine) or maybe a curry house. Tandoori, Balti, etc. all relate to styles of cooking and may be used in restaurant names, but if I was referring to restaurants that serve Indian style curries in general, I would just call it an Indian.
*Curries unless you’re talking about the electronics retailer
If you’re just referring to the restaurants, I’d just call one of those restaurants an Indian (as in the cuisine) or maybe a curry house. Tandoori, Balti, etc. all relate to styles of cooking and may be used in restaurant names, but if I was referring to restaurants that serve Indian style curries in general, I would just call it an Indian.