I read 'Oxford in the Great War' with interest, but there is something wrong with the photo 'Conferment of degrees'. All those in academic dress seem to be wearing D.Mus gowns. It includes Sydney Watson, Thomas Armstrong and Ralph Vaughan Williams. But Watson was only 11 years old in 1914 and Armstrong 16. Vaughan Williams was 42, but in the photo looks much too old to be about to volunteer for active service in the army.
Is the cleric on Vaughan Williams' right Rev. E.H. Fellows? He received an honorary D. Mus in 1939, so perhaps you've got the wrong war.
If this is not so, can anyone shed any light on the photo?