I now realise it's the curry cooking stage itself that needs the greater amount of added oil, to little and you end up with a boiled sauce.
not tasting well at all.
Okay, THIS screams of similarity to Chinese and stir-fry technique. I've spent a bit of time getting that whole thing figured out within the present limitations I have (normal stove). Especially when stir-frying meats or watery vegetables, it is easy to drop the wok temperature if too much is added at a time, and that results in the juice leaving and boiling instead of frying. I end up doing meat in 3-4 batches with the burner cranked, since it is the most dense item as far as absorbing heat is concerned. Before I start I preheat the wok, then preheat the oil, then begin (and meat is at room temp as well).
I believe that the ultimate key to mastering technique on home stoves is not overloading the pan AND being patient. Too much addition at one time = temperature drop = no frying. I actually use a small ladle for adding base (2 oz / 59 ml) for this very reason. When I start a dish, enough oil has to be present to properly fry the ginger/garlic, spices, tomato, etc. until I am ready to add the base. Then I also have to give enough time for the base to properly reduce and start caramelizing before each additional ladle.
Resorting to longer cook times, and thinking things look a bit "cooked down" at times before adding additional base has helped with flavor consistency and intensity. The final fry-down is watched most carefully with the final ladle (and finishing additions) until the sauce has reached the proper consistency. My take is that every single reduction, with the addition of base, gets cooked down and concentrated/caramelized. The more effectively this happens, the more punch the sauce ends up with.
When I stopped trying to emulate videos so much, I got much better results. Now, if I had the same equipment they do in the video, then I'd have a messy/burned disaster if I tried to deviate too much from their techniques as-shown, or would be cooking on super-low flame at all times.
I find that I've really been cooking some excellent curries as of late, and this new base looks like it is going to be a further boost to them.