Hi Barry, Firstly here is the file where the magic happens, in there is extrudeMeshDict which can be edited in the future to extrude other meshes:
https://1drv.ms/f/s!AmmuZY9R6wFaiL0CJsthSpJacms3Gw
Secondly, I created a video on how to do this so you can hopefully do it at your leisure:
And finally here is a project which I uploaded the 2D mesh:
Also, I recommend improving the quality of the extruded face:
As you can see this will likely skew results, I find that this is usually improved if the bounding box slightly intersects the geometry it is meshing so that the face to extrude would belong to the bounding box, not the geometry.
Any questions feel free to ask 
Best,
Darren