I love the film 'Withnail and I,' & recently noticed the 'I' character reading this play during a scene in the movie - presumably it's the play in which he ultimately wins a part. This prompted me to order a copy from Amazon, and guess what? It's not bad!
It's a thoroughly British portrayal of life in a WW1 trench. It's not perfect - there is more than a hint of stereotypical caricature in Sherriff's depiction of various working class/public school characters - and it seems rather sanitised compared to Remarque's superb description of trench warfare in 'All Quiet On The Western Front,' but you are drawn in by it all, and I'm sure the script would gain a lot & be very affecting in performance.