Here is a little tip the chef at my local TA has shown me to speed up removal of excess separated oil from a curry.
When your curry is nearly ready, carefully (off heat) tilt the pan towards you (e.g. at an angle of about 30 degrees or so). The separated oil on the surface of the curry will slowly start to run downwards. To speed things up, pour/drizzle a small amount of base gravy over your curry (with a chef