This page lists several GotA behind the scenes documentary extras as
being scheduled for Starz On Demand from 22nd Jan onwards. I would guess they're pretty much the same content as the videos on Starz's youtube channel

Spartacus: Gods Of The Arena Extras

Go behind the scenes of Spartacus: Gods Of The Arena. See this new
original series by Starz beginning January 21 only on Starz!
Starring: John Hannah, Lucy Lawless

Episodes

AUSXIP Reporter: Barbara Davies