I've latched on to this fella, used these 3 so far and really enjoyed the results, as stated it is a bit of a chore initially but having done the base gravy 3 times now it's become a doddle, same with the madras, obviously you can make adjustments as you go but tbh I wanted old school Indian restaurant style rather than proper Indian food, I'm sure the base gravy was just created for us as we like sauce/gravy with our food.
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There are plenty of other contributors on youtube but this one suits me, got the ingredients from Noor cash and carry on Finney Lane by Heald Green station, more of a supermarket really but they stock absolutely everything you will need, relatively inexpensive as the spices etc last for ages. One tip, seal all the packs of powders etc in plastic tubs or your kitchen will smell like Rusholme 24/7.