Well, I did say i wanted to learn 
before opening Harvester.gh…
instantiate was the verb I didn’t know I needed.
That took me to:
which took me to:
https://developer.rhino3d.com/wip/api/grasshopper/html/Overload_Grasshopper_GUI_Canvas_GH_Canvas_InstantiateNewObject.htm
ok. I guess I need to load the namespace in a python componenet, and call the correct guid to get the component (to then interogate).
Hmm. How to get guid?
Right clicking on the compnent icon in menu bar in grasshopper lets me bring it up (although sadly, I can’t select the guid out of the text).
Could I set my own? https://developer.rhino3d.com/wip/api/grasshopper/html/M_Grasshopper_Kernel_GH_Attributes_1_NewInstanceGuid_1.htm
nope, a couple of inches and one more celtic saint required for minimum requirements. let’s have a look at Harvester.