Nice to see that you're using kashmiri red chillies and not paprika which just doesn't works. Also, add 1 tsp of the chilli powder and turmeric to the marinade. It will give the chicken the tempting reddish- yellow.
The fresh tomato is actually traditional though not diced. the sauce is also usually blended smooth before adding the chicken. Overall its a pretty good recipe.
the grill tends to just have two setting in ovens, HOT and not quite so hot, I am not sure in this regard, my thoughts are as its coated with yoghurt you would want it on the not so hot setting but on the other hand, this chicken will be partly twice cooked, so you want the intense heat to crispen the outside leaving the middle underdone before then finishing it off in the sauce.
the dried Fenugreek is really only sold in speciality Indian grocers here in Australia, I think she may have not used it due to this reason, fair bit more difficult to get the ingredient. Mace blades are also used in the original butter chicken recipe, an ingredient even more difficult to track down I found.
