In one section, of the book, on interpreting the Text, Craddock suggests this:
The Evangelists preserved and interpreted sayings and events from the ministry of Jesus. In addition, it is generally, though not unanimously, agreed that Matthew and Luke used Mark’s narrative as a basic source for their own. One’s investigation of a test in Matthew, therefore, may reveal that Matthew is interpreting for his church a passage from Mark which is a record of a saying of Jesus (Craddock, Preaching, 119).
Maybe… just maybe… I have detected some Barthianism in his writing… so maybe some Austin Farrer – or at least, he is a wise enough man to realize just how BUNK Q is.