At the beginning of July 1915 Gwynne was acting as chaplain to the 5 Bde. It was responsible for a section of the line around the town of Bethune. The trenches that made up the opposing sides had come into existence in November 1914 when the period of mobile warfare came to an end. They would remain in essentially the same place until the final battles of 1918 almost exactly four years later. As with other chaplains, Gwynne was attached to the FA that provided medical cover for the brigade. From that base, he visited the units in the trenches and in the rear areas.

On 17 July, he received a summons to the WO. On reporting to Bishop Taylor Smith, the CG, he discovered that he was to be appointed as a DCG. He was thus promoted overnight from being a chaplain to the forces class 4, with the relative rank of captain, to a position with the relative rank of major general. He spent the remainder of the month in London preparing for his new rôle.

1 July

All my flock are now in the trenches at Givenchy or lying back in Reserve near Gorre or Le Preolan. Once more I am too far from my Brigade and am trying all I know to get nearer to them. I visited the Worcesters in their Billets and had tea with their Officers who are billeted in a good chateau with a fine garden. I had a few shots at target with a rifle, but did little good. I also paid a visit to the Brigade Head Quarters to find out whether I could get hold of a billet nearer the troops and how long the Brigade were to hold the line at Givenchy. Everything seems quiet along our line and there is comparative calm in the fighting. Now and then you hear a crash out of a hedge and the Germans always reply. One of the Oxfords was killed today by a sniper. He got out of a trench and with a couple of sandbags to protect him, tried to shoot a sniper who was causing a lot of trouble. He had fired about 16 shots when he himself was shot dead, the man's name was Lemount.