World war one commemoration - songs

When I was little, my dad used to teach me songs he'd sung during the war, sometimes to my mother's horror. He also had a wonderful Warren Mitchell album, with the actor in the guise of a WWI soldier, singing marvellous songs like Dolly Gray. I can still sing most of those off by heart. I'd recommend finding any of these little gems on youtube.
Many of these have stood the test of time - my daughters were taught 'Tipperary' and 'Pack up Your Troubles' as part of their WWII project at school. (And those two songs are great sung in counterpoint.) Max Arthur's book "When this Bloody War is Over" is also a great source of both lyrics - not suitable at all for little girls like I was! - and tales of concert parties. I recommend it highly.