Aha! Logging this for anyone interested.
max_velocity - from [TRAJ]MAX_VELOCITY was a big disappointment - ini files now appear to set MAX_LINEAR_VELOCITY so max_velocity always returns 0.
However, I somehow missed stat().current_vel which in combination with motion_type (value of which changes when running a program) should give me both the actual feed rate ( MOTION_TYPE_FEED) and the actual rapid rate (MOTION_TYPE_TRAVERSE).
We shall see - and I still have to work out what to do with the other motion types (esp arc).
