Thanks guys. It's amazing how much heat an energy efficient LED makes. With out the sink these things get over 100C in seconds.
The dimensions for the light are 2.30" by 2.60" at the base (It tapers at the face of the lens to 2.50 X2.20) The mounting flanges width across the light is 3.28".
The lights are still bigger than I wanted but they will fit in the standard Kitfox wingtip but you have to mount from behind. I am going on a ski trip for the next 5 days but when I get home I will mock up how it will look in a Kitfox tip with a 3D printed mock up lens.