Bugsy, you could try finding the reprints of the "Wipers Times" which was a sort of WW1 underground newspaper in "the Salient", I saw a bound set of reprints in a library years ago, in London. It had poems and lyrics of songs in it as I recall.. might be a useful source of background, try here http://www.adam-matthew-publications.co.uk/COLLECT/P119.HTM or try and find this
The Wipers Times. A Complete Facsmile of the Famous World War One Trench Newspaper (London: Peter Davies, 1973). 940.4144 WIP