Thanks n.igma, I have skimmed the article and will read it in full shortly. Although as you say it isn't directed at
Philip II specifically it looks like an interesting overview of the general question of the use of marks on Hellenistic coins.
Peterpil19 - thank you, your efforts haven't been in vein! The second article you linked to references this
work, G.
Le Rider, Le monnayage d'argent et d'or de Philippe II frappe en
Macédoine de 359 à 294, (1977), as being the "first and only comprehensive study of the coins of
Philip II".
I didn't see it in stock on Amazon or Abebooks but have located a pdf copy of Le Rider's book via
google (I won't link to it as it looks like it is
still under copyright). As the title suggests it is in
French (which I don't read) and I am not overly familiar with the format of academic coin texts so it is difficult to give a cursory overview but it does have a section on
monograms (albeit that while bronzes are mentioned the focus seems to be on Philip's silver coins). In the unlikely event that I make sense of it I will let you know.