Please DO NOT add to this discussion.
According to Wikia Contributor [[1]] we should not list Series 9 episodes 5 and 6 as a two-parter because it is not a two-parter, however it has been told that these episodes are just not a "conventional" two-parter but more of a linked story, and I would say it is appropriate therefore to list them in one box. He also states that episodes 9 and 10 are not a two-parter either, however these two episodes being the only two left, and Justin Molotnikov having been signed for a two-parter, contradicts this.
He said: It states clearly on the official Doctor Who website that 5 and 6 are not a two parter and that 9 and 10 are not a two parter
I wasn't able to find this "official Doctor Who website" myself, and no link was given. I don't want to begin an edit-war with this person.