MLE ('Long-Lee') cleaning rod guide early type No2
This tool also fits the P14 muzzle
These were used to prevent cord wear on the muzzle from the pull-through. Over time the pull through cord can wear a groove in the muzzle.
"Notes for Instructors on the Use of the Rifle October 1918 (General Staff 40 WO 6969). It does specify 'one steady pull ... to avoid cord wear'"
Most have PH (Parker Hale) markings.