I just looked Closer at the beautiful front page frame of all "blades" by Mark A...
I like the classification of having that huge "Perd" in the group of blades..
I vote PERD Blades have a seperate page of their own along with the Ensor blade & Darl blade.
ALSO of note that I like, bottom R, a seeming dart point...but like Many "points" that are very commonly found..one side is obviously worked down, presumably after being used as a penknife ( blade ).. it's perfectly at home in a blade frame.