We found this on Hill 112 a few years ago, as best that I am aware it is part of the fuse/nose cone of a 25lb shell. It was just below the surface adjacent to a pathway from the memorial site / main road to the forest area which is about 200 yards away. A small item but who would have wanted to be hit by it when the ground was being fought over, no doubt this shell and others like it took a grim harvest of life, British, Commonwealth and German. The second item came from the crash site of a 240 Squadron Catalina which crashed in County Letrim on 21/03/41, the operational debut of the Catalina/ PBY. All onboard perished, some terribly burnt, engine trouble made them turn back and unfamiliar with the local high ground they struck a mountainside. ( I have no idea what this is AM marked and numbered, the .303 is from the same location.
I've also found parts from fuses and plenty of bullets during my trips to Normandy, but I've never seen anything like the other item you have. I'd assume that as it's Air Ministry marked it could be part of an aircraft or equipment. The last time I visited Hill 112 I found a number of British and German bullet casings on the track that leads around the back of the woods. I was quite surprised to find them just lying on the surface rather than being buried in the ground.
A Day after the burial of the aircrew killed, Irvinestown Church of Ireland, same graves as seen today.