One of his chapters is entitled "Sacraments?" and in the course his reflections he has this to say about John 6:51c, 53-56:
"Since it is distinctively eucharistic language that appears in 6:53-56, it will almost inevitably call the Eucharist to the minds of Christian readers familiar with that language. We must reckon seriously with this "overtone," but at the same time we should not allow it to replace the primary meaning of the text. Responsible readers who recognize the eucharistic overtone will understand it in a way that is consistent with the primary meaning of the text. There is nothing in the context to support the view that John was actually warning against an unacceptable sacramentalism in which too much importance was attached to the material elements of the rite.* But the passage surely resists any eucharistic reading of it in which the material elements of the rite take the place of the faith in the crucified Jesus that it is primarily about. In other words, the Eucharist can be relevant to a reading of the text only insofar as the Eucharist is understood precisely as an expression of faith in the crucified Jesus and as a symbol of participation in his life. Then the text can function to teach participants in the Eucharist what the sacrament is actually about. At the same time, it is vital to recognize that while the Eucharist is the communal rite that focuses what this text is about in the life of the church, the meaning of the text exceeds the Eucharist. The primary meaning is both more basic and more extensive than the sacramental overtone." [p. 103; my italics]
*That blows away one theory of mine!
At the heart of Anglican Communion life is, well, communion and it is important that we understand (as far as we are able this side of the Parousia) what communion is and is not.