User:SOTO/Forum Archive/The Panopticon/@comment-9435571-20151118033620/@comment-9435571-20151119172518

"The main question I have here is, does "Black Hole" explain why 2 had grey hair and why Jamie, who is in his teens in the 2D era, is suddenly in his twenties during "2 Doctors"?"

No, but it's no different from how actors sound older in Big Finish audios or how Hurndall replaces Hartnell in "The Five Doctors" - something that we can simply ignore and don't need a special reason for.