The following sources have potential matches based on the name and other information associated with this record. They may or may not be connected to this person but are provided for your further research
The regimental War Diaries are held at The UK National Archives and as of April 2020 have been made available for free download*. They are the official unit war diaries for the British Army that contain records of daily activities, including casualties. They are not personal diaries.
* you will need to register for an account and login to get access to the downloads. When following the link from any record be sure to make a note of the page number. You will then have to download the full diary in pdf format and search for the respective page and hence entry.
Lance Corporal Mcmahon
Date of death: 01/07/1916 (aged 30)
Cemetery: GEZAINCOURT COMMUNAL CEMETERY EXTENSION
See "CASSIDY," the true family name.
Serjeant John Mckay
Date of death: 18/09/1918
Cemetery: ETAPLES MILITARY CEMETERY
Also known as J O'Regan