This was still using the PPPoE with Slingshot account credentials though.
Seems it doesn't care - I had a strange issue with my Fritzbox where it wouldn't let me do IPoE without a username/password (this has since been resolved). I had to have something in there otherwise it wouldn't connect. I'm guessing thats why yours did too with the slingshot credentials.
@Lizard1977 - did you take the plunge and swap over?
Yep, I switched over to Orcon, but my connection date is not for a few weeks yet (30 days notice required for Spark).