Although I lived in Oxford for six months, I must say I never had any trouble with the ghosts, but then we all know that dear Lush attracts special interest, even from beyond the grave!
Perhaps the shade in question was a roistering Cavalier, see this link
The Eagle and Child
After all it was said that
"Admittedly we Cavaliers have the sins of men, drinking and wenching, but the Roundheads have pride and spiritual rebellion, the sins of devils"