This is the final image lit with IBL.

And this is the final image using our own lights.

Personally I prefer placing the lights myself as opposed to IBL just because I can get it looking exactly like I want it to (for a piece thats entirely animated anyway, if I was doing a VFX shot with live action plates then IBL would be ideal). At the moment, having discussed it briefly in the group, we think we will just place the lights ourselves. We hope to have the modelling for the project finished by the end of this week so we will look more in depth at the lighting set-up then.