Richard E Grant (in-universe)

Richard E Grant was the actor who portrayed the character Withnail in the arty film Withnail and I. Ace saw the film several days before being transported to the Iceworld, and upon seeing the film, had developed a crush on the "gorgeous" actor, comparing him to the Seventh Doctor who she felt treated her like an unintelligent child, wondering why the Doctor couldn't be more like Grant. (PROSE: Independence Day)

Behind the scenes
Ace wondering why the Doctor couldn't be more like Grant was likely a joke about Richard E Grant's portrayal of the Tenth Doctor in the Comic Relief special The Curse of Fatal Death.

In Doctor Whoah! 376, Richard E Grant was alluded to when the Ninth Doctor mockingly referred to the other Ninth Doctor as "Withnail".

Both Richard E Grant and Paul McGann exist in-universe, an unintentional coincidence. However, unlike the in-universe Paul McGann, there has been no valid source that has identified Richard E Grant to have starred in the in-universe Doctor Who franchise.