Thomasm,
i think there are a few existing posts on the health issue. might be worth a search.
it's clear BIR curry is something to be had in moderation.
for me the salt is a bigger concern than the oil. i'm hoping the use of msg might allow me to reduce the salt but it's a pipe dream at the mo.
on the oil u can reduce the amount in the base to typ 3% (based on the initial chopped onion volume). at cooking stage by cooking slowly u can reduce the amount of oil needed probably down to 1 tbsp. u could also switch to olive oil if u have the need.
on an aside - i also know that the best curries i've tasted don't have hardly any oil on the surface. this begs the question for me as to how much of the cooking oil stays in the curry as most seems to convert to smoke when cooking on high heat.
whilst keeping moderation in mind i do feel there is much hype on health. i've regularly had medicals and monitor my cholesterol. i also eat a lot of curry and actually believe/feel i'm healthier for it. i'd also add that i'm well aligned with your good lady - i too being serious about eating healthy. i guess if i'm wrong in the curry belief then i must very successfull in offsetting it in the rest of my eating. i'd never have butter on a sandwich or sugar in tea/coffee for example.