Who was the bishop in the apparition at Knock?

On the night of the 21st of August 1879 the Virgin Mary flanked by St Joseph and a bishop thought to be St John the Evangelist and an altar with a lamb and cross on it allegedly appeared on the gable wall of the Parish Church for a few hours. Fifteen people witnessed the vision including a child of five (page 60, The Evidence for Visions of the Virgin Mary) and stood watching it for two hours allegedly in torrential rain.
The witnesses saw a bishop with a mitre and a hand raised in blessing holding a book in the other hand. They strangely decided that this was St John the Evangelist. Why not St Patrick? That would have been a more natural assumption. It was said the image matched a statue of St John in Lecanvey but it has never been established that this statue existed and it didn't wear a mitre. A true vision would not leave people guessing. A Protestant policeman engineering a hoax might. He wouldn't understand the Catholic religious mentality.
The Apparition at Knock (page 79) says that because the altar and the lamb in the vision come from the book of the Apocalypse written by the apostle John then it's a hint that the bishop was John. First, of all, modern scholarship says that the apostle John did not write the Apocalypse. Tradition which is unreliable says he did. So if the vision intended to hint that John wrote the Apocalypse the vision was certainly not from God. Secondly, would it be wise for a true apparition from God to get involved in the dispute about who wrote the Apocalypse? Of course not. Thirdly, it is not flattering to make a link between Knock and a vindictive Bible book where Jesus and the saints are portrayed as vindictive. There God and Jesus plot new ways to torment the world and the saints cry for vengeance.
It has been observed that the image of the bishop could have been of widely adored Archbishop John MacHale. As he was not dead, the witnesses could not say the bishop was him. If it was meant to be a representation of MacHale, then clearly the apparition was a joke. There are some pointers that Archdeacon Cavanagh manipulated the facts to make it seem like that the bishop was John the Evangelist (page 196, Knock, The Virgin's Apparition in the Nineteenth Century).

The odd thing was the bishop supposedly looked in the direction of the schoolhouse where they all stood.  That would mean when he was first seen and there was nobody standing at the schoolhouse that is more than a little strange. 

It seems more accurate to say the bishop looked in the direction of the east as some witnesses said.  That gives an even stranger direction.  See the map below.  Such oddness smacks of a hoax.