I thought I knew most of them, but I don't recall this one. The first 4' 30", obviously a feature film but not one I recognise. It seems to be Somme-themed. Maybe an extract from the 1927 film? The rest of it is a mish-mash of genuine Great War stuff.
"Sometimes things that are not true are included in Wikipedia. While at first glance that may appear like a very great problem for Wikipedia, in reality is it not. In fact, it's a good thing." - Wikipedia.