Plodding on with this I have programmed a 5/16 plain slot drill to mill the round pockets as simple 2d pocketing operations - the same cutter then mills the full depth of the 2d element of the part with another 2d pocket (toolpath boundary by extracting edges from the part geometry), then a further 2d pocket mills in the shallower rib. I then go in with a .125 diameter ball nose mill and create the radius using a Z level finishing program running just over the depth of he radius by specifying top and bottom of job. This gets the 2d bit sorted reasonably efficiently I think. It certainly looks good in Predator.
Thinking now about the 3d element I am thinking advanced roughing with a 5/16 ball nose mill? Not sure about the finishing paths after this though.