After printing the mooring hook https://www.printables.com/model/1636340-mooring-hook-rope-over-tree-branch-tool I thought of a system to attach it to the Gardena combisystem. Mainly this is a 12 mm hexagon with a cylinder that slides into the telescopic handle.

If anyone needs to adjust the model to his own requirements, there's a FreeCAD file attached.

The design can be printed without any supports because its flattened on one side. I printed mine in PLA 0.2 mm normal mode with 20 % gyroid infill.