I took the advice to go out and make some photographs seriously and here is the result...
I also took the opportunity to persevere with my quest to master FreeCad. About four days of intense banging my head against a brick wall and it's slowly beginning to make sense. I can now create the shapes I want (well some of them!) and for the most part place them where I want to place them. I have watched hours of YouTube tutorials about FreeCad, some make sense, others were a waste of ether space. Two particular videos unlocked the software for for me, one in Italian, and the other with a robot dialogue!
And I don't speak Italian...
This is my first successful effort, it clearly shows the form of the curved Arca rail which will form the backbone of my Panorama head.
The outer dovetail cut is not quite right, too deep by a couple of mm or so but that's a detail, I will re-draw it once I have constructed the rest of the head. I am currently struggling to form a hole on the base block at 90º to the current drawing axis but having read up some info and slept on it, I think I will master that today. I almost had it last night but when I hit the cut button it all vanished from the screen! LOL
Good to be back, many thanks for the suggestions for CAD software. The main reason I had avoided 3D was I found it very difficult to comprehend, not the 3D concept but the totally strange way in which the drawings and shapes are generated. So excepting for some insurmountable obstacle I shall stick with FreeCAD for now at least. It's slowly falling into place in my mind. You are never too old to learn. Learning opens up the future.