Hi David,
What would AG/8N/2593 represent on the Long Service and Good Conduct (LSGC) Medal register for Trooper Wheatley A J, 1919, 1st Life Guards,July 01 1915 (WO 102 18)?
I thought it might say "AG/SN/2593", but I looked through several pages and found better images next to other soldiers records.
Best wishes,
John Wynne
PS:
I've loaded a picture of the entry.