Following a recipe isn't difficult and I didn't botch either. The Bhoona is good. The Korma was not, but I now understand it to be a classic example of BIR Korma, as demonstrated by The Curry Kid among others.
The Bhoona: Would you taste and tweak the frying of onions, garlic and ginger? Maybe in the middle or end of 10 minutes bhooning the spices or immediately after adding the raw lamb, tomato, salt and sugar or after the initial 10 minutes cooking the meat? At none of these points will you know what is going to present and you would likely have to rinse your mouth. You are trusting the author. Only after you add water and start to reduce the sauce and cook the lamb can you tell what you have. Not much you can do at this point. Adding 2 TBSP of Garam Masala was clearly not something I would do so that was easy.
It is interesting that the last instruction is to test the sauce. For what? It doesn't say. Nor does it say what to do if it isn't right. You can't remove the excess black cardamom.
Having now cooked it, without half of the specified Garam Masala to finish, I feel able to cook it again with the simple removal of 1 black cardamom. Please inform us of the other obvious tweaks you made and at what points you did tastings and what to test for George.
My usual practise is to follow a recipe closely on the first occasion and make changes after that.