The DLI number looks like a pre 1917 Territorial one (they went 6 digit in 1917) Cant be Regular Batt (1,2) as that number(4464) was issued well before WW1.
He didnt deploy overseas u ntil after Jan 1916 as no star issued
Looking at casualties 4463 Was Killed In Action in Oct 1916 with 1/6th Batt so think this would be his Battalion(although he may have been in 2/6th before as he didnt go overseas until 1916 and 1/6th went 1915 so he may have been a casualty replacement?)
Do you know if he was in Salonika?
The Medal Roll book at Kew Should confirm Batt but isnt online
Ady