Hi Steven… I think you have nailed it as near as possible with the tools available in DT! I have brought up the exposure and added a little contrast to your style on this image and it is virtually identical tonally to the JPEG I generated form Olympus Workflow - the green is still off but like you say, Olympus are adjusting colours in camera based on the scene I think, hard to replicate globally. Who knows, these are a long time ago with the EM-5 I no longer have and I may have select landscape mode or something in camera who knows!!
Just shows what DT is capable of though - well done!
*Edit JPEG on the right.