My understanding is this:
1. smooth, green painted helmets, with or without holes punched through the brim either side of the chinstrap fittings were for home front use.
2. textured green helmets were issued to the regular army and home guard.
3. textured green helmets with holes punched through the brim were issued to the home guard.
Therefore I would suggest your helmet was for early war home front use but who knows, perhaps someone in the home guard wore it until a textured khaki helmet was issued.