Thanks CH. Yes I ask such questions more to know what the general consensus is, so as to have that as the basis on which my continued attempts will be compared. I don't think for a moment that what any one person says here will be my holy grail, as in any case, there is healthy arguments about almost everything here.
My 1 1/2 year BIR journey has so far taught me that the base sauce offers most influence, and that less is best; I don't think I've under spiced a curry yet. So I did keep my Madras simple. No fenugreek, no garam masala, no fresh coriander. Clearly then the base sauce and the chosen spice mix played a big role, but the lemon did give it an edge.
Staying on subject of the OP, I've never really taken to either Madras or Korma, but I have tried them in the BIR from time to time. And yes, my first ever attempt at Korma struck me as being exactly like the ones from the restaurant, but I should say that also the Madras was pretty OK. I think the cream in the Korma reduces the influence of the base sauce and means that almost any attempt comes out similar, while the Madras is very low on additions, so the base sauce and spice mix are big players in determining the flavour, so more difficult to replicate, if that's what you are looking for.