PaulP , Sorry to read of your poor result

I have now probably made this over a dozen times and have never had a ' bad one ' , it sounds to me something went wrong somewhere , the 1 hour seems a long time to be frying the Onions but if the end result is the same it shouldn't matter i suppose , the 1hour (minimum ) simmer i think is very important and i simmer probably 11/2 hours as this gives the ingredients and meat time to cook down and release their flavours into the sauce .This is a ' slowboat ' way of cooking a Curry compared to BIR style but once simmering gives me the time to do the Rice and Bhajis.
I cant figure out why you had an overwhelming flavour of Ginger I've never had that

I have handed out about 10 of these Recipes to the Guys at work and they cant get enough of it

Give it another go PaulP, follow the Recipe and don't rush the simmer

ATB.