Holy Mother Church has firmly and with absolute constancy held, and continues to hold, that the four Gospels just named, whose historical character the Church unhesitatingly asserts, faithfully hand on what Jesus Christ, while living among men, really did and taught for their eternal salvation until the day He was taken up into heaven (see Acts 1:1). Indeed, after the Ascension of the Lord the Apostles handed on to their hearers what He had said and done. This they did with that clearer understanding which they enjoyed (3) after they had been instructed by the glorious events of Christ's life and taught by the light of the Spirit of truth. (2) The sacred authors wrote the four Gospels, selecting some things from the many which had been handed on by word of mouth or in writing, reducing some of them to a synthesis, explaining some things in view of the situation of their churches and preserving the form of proclamation but always in such fashion that they told us the honest truth about Jesus.(4) For their intention in writing was that either from their own memory and recollections, or from the witness of those who "themselves from the beginning were eyewitnesses and ministers of the Word" we might know "the truth" concerning those matters about which we have been instructed (see Luke 1:2-4).
This, to me, seems pretty straightforward. The Gospels tell the "honest truth about Jesus". They aren't always rigid histories in the strict chronological sense -- they don't always agree on chronology, for one thing -- and some events and people are syntheses of multiple events and people. But everything they describe, or something very much like it, really happened.
Compare that to Bp. McGrath's statement:
[T]hese sacred books are not historical accounts of the historical events that they narrate. They are theological reflections upon ... events ...
This statement is internally contradictory. What does it mean for something to be "not a historical account" but to nevertheless "narrate" "historical events"? But the real question is whether the bishop is trying to say that the Gospels are only "theological reflections," and not also "historical narrative," albeit historical narrative written in the style of eastern Mediterranean Jews and Greeks 2000 years ago, not in that of 21st Century Americans. With that idea, if that's what he's saying, I think Catholics ought to strongly disagree.
I agree. I think that you have nailed it