Paul Vanezis has put a further nail in the coffin over at the Missing Episodes forum:
I outlined on Gallifrey Base some time ago how I think this mutated from a list of titles I created for the DW production office of what could potentially be still out there(around the time Air Lock and Underwater Menace were returned) to a mixed bag of 44 episodes or thereabouts, to the bizarre figure of 90, which is a new one on me.
That initial 'chinese whispers' rumour just got repeated and embellished and when you want to believe and every Tom, Dick and Harry has a theory, then this is what you get.
People have been wondering why I didn't step in sooner and "nip it in the bud". Well, I have better things to do with my time than repeat myself on a DW forum. People wouldn't believe me anyway.
People know that I believe it when I see it. Here's a new one; if it sounds too good to be true, then it probably is.
Even that won't be enough for some of the people in the Gallifrey Base thread, who (until it got temporarily closed again) were busily suggesting that the TIEA denial was a lie requested by the BBC, that the wording wasn't definite enough, that there was something suspicious about the whole business. They demand official statements from everybody and their brother, poke holes in any statements that are made, and then act surprised when Vanezis and others don't bother debunking every new iteration.