Adding a Faerie Dragon familiar?

[Barwickian]

I'm unable to add a faerie dragon familiar to one of my players' characters. It just isn't showing up in the list of available familiars.

The character is an NG Oracle 7 with Eldritch Heritage (Arcane), Arcane Bond (Familiar) and Improved Familiar. I have all the bestiaries and familiar packs loaded in Config.

Just to check whether or not it wasn't recognising Eldritch Heritage, I created a test character, a CG Sorcerer 7 with the proper feats. Still no dice.

I even tried creating a custom faerie dragon in the editor and dropping the requirements for an advanced familiar, to no avail.

I'm obviously doing something wrong - searching the forums suggests others have no difficulty.

Does anyone have any clues what I might try next?