Pattern 1914 Haversacks
Well spotted !
It's ok, I don't need a link It was singing "1914 pattern" at me in the original photo... I just wanted to be sure
It's definitely a 1914 Haversack with it's rear tabs and bottom buckles removed (third type as you say). It looks like it still has it's original 1914 Pattern side buckles though, which is very rare (these are tongued buckles right?). A huge number of these packs were converted (even during WW1) to 1908 Pattern by replacing the side and bottom buckles (these are often called 1908/14 Hybrid or Convertible or some such thing... but they're not).
That's a really nice find! If you added it to a 1914 Pattern set in 'marching order' it would look fantastic