BB1 - thank you for your suggestions, which I will experiment with,  I have now fitted a new central burner to my tandoor oven as seen in the attached image. It produces a much healthier looking flame than the awful yellow, sooty flame of the original, wholly inadequate burner ring. I removed the original ring with an angle grinder and then cut out part of the bottom of the oven with tin snips. I should add that it's wholly thanks to you that I bought the new burner ring on amazon in the USA. There was no request for duty or VAT so maybe it's included in amazon's handling fee,.

Thanks leeroydan. The recipe was one of mine. 1 TBS veg oil, heat on a medium flame, add 1 tsp ginger/garlic paste, 2 tsp diluted tomato puree and pinch of ground up methi leaves. Sizzle for a bit then add 1/2-1 tsp of mix powder, 1/4 tsp salt and just under 1/4 tsp ground cinnamon. mix this and add a little base sauce to prevent burning and fry for about 1 minute. Add 1 ladle of base and increase the heat mix well. Wait for the sauce to reduce then add 1 portion of precooked chicken and about 1/2 tsp brown sugar. Mix well then add a good sized handful of fresh spinach and a little water. Put a lid on and let the spinach wilt then add another ladle of base sauce, chopped coriander and a few slices of fresh tomato. Allow the sauce to reduce and stir occasionally then add another half a ladle of base. Reduce the sauce to the consistency you want and serve. 

The recipe would accept a little chilli powder if you want some heat, I would add 1 or 2 tsp with the mix powder and add a little lemon dressing and omit the sugar.
 
All the best

Rob