Enfield No4 Mk1 Identification Help

[krinko]

The sloppy EP marking is typical of a 1943 Fazakerley. Location of the marks is normal, as is the serial number.
At that time, FAZ was running three sets of serial numbers concurrently, with a funny prefix system. The second letter of the prefix indicated which "line" produced the rifle, _A, _B or _C.
The first letter indicated the "series" produced by that line and changed when the serial number got to 99999.
So when AA got to AA99999, the prefix would switch to BA, then to CA etc.
Likewise the AB would switch to BB and then CB; the AC would switch to BC and then CC.
-----krinko