Thanks for the idea.

There is a page for the Shape.Adjustment property here: https://learn.microsoft.com/en-us/office/vba/api/powerpoint.shape.adjustments and this finally worked:

  # If shape is a msoShapeArc
  if($shape =~ /msoShapeArc/i)
  {
    # Set the start and extent angles of an arc
    $new_shape->{Adjustments}{1}=$options->{start};
    $new_shape->{Adjustments}{2}=$options->{extent};
[download]

I was using a perl list reference of a 1 in square brackets when it was just another hash key deeper like {1} and then it WORKED!!!

Thanks to you both for assisting - having someone to bounce an idea off of helps!