The First Regimental Battle Insignia?

On  26th January 1915, a detachment of officers of the 2nd Battalion who were in the front line near La Clytte, ventured  via road to Merris some 11 miles away to find their counterparts in the 1st Battalion who had recently set foot in France. It was the first, although partial meeting, of the two Battalions on active service for some years.
Lieutenant-Colonel Clifford, commanding 2nd Battalion, met Lieutenant-Colonel Wallace, commanding 1st Battalion and lunched with him at the 1st Bn HQ Billet.
Others in attendance were Captain and Adjutant of the 1st Battalion, D.V.M. Balders and Lieutenant and QM Godbolt.  
The 2nd Battalion's entry that day in their War Diary noted this historic meeting and remarked that men of the 1st Battalion were "decorated with little yellow castles below the collar on their backs” - was this the first instance in the Regiment that a distinguishing battle patch was worn?

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