I would disagree on the national dish question, whilst Chicken Tikka may be very popular (Similar but nor exactly the same as Butter Chicken, which incidentally is rare in the UK) the mostly recognised national dish(although there is no official designation) is Fish and Chips.
Also you wrote the date in the US way rather than UK, we very rarely do this.
2. Search on Google "UK National Dish" it is called chicken tikka, or butter chicken.
Also you wrote the date in the US way rather than UK, we very rarely do this.