I'm okay with him knowing and 4th walling Narvin for general Doctor Who stuff-- knowing who the Doctor is, what TARDISes are, Time Lords, etc--but I'd rather not have Narvin 4th walled for things specific to his spin off. He's got enough angst wondering whether his universe is actually an AU. If he's told it's also fictional, his head might blow up. (And even in geek circles not many people listen to the audios anyway.)