I don’t know why, but I now have an image in my mind of Jonathan Letcher cannibalizing an unplayable Pakistani harp for tuning pins to fit his tuning key.
Good to hear that the photo gave you a useful lead.
My tuning key was custom-made for the harp which Jonathan made for me, so I’m sure it is the correct one! Looks like it’s made using the same wood he used for the harp frame. Tuning is so easy using this key because you can get a really firm grip whatever the angle and make very fine adjustments without much effort.