Howling:Who is Gus?

Well, I was just generally wanting to discuss who we think "Gus" or "GUS" was from the TV story "Mummy on the Orient Express". I have generally heard most people saying that "Gus" is Seb from "The Caretaker", "Dark Water" and "Death in Heaven", but is "Gus" even linked to "3W" and The Nethersphere? Do you think we will return to "Gus" in a future series, or do you think he will remain shrouded in mystery? All comments and theories on Gus' identity will be greatly appreciated. Thanks: 19:29, November 4, 2014 (UTC)