Identify my Enfield

[dand883]

I have an old .303 enfield i got from my grandfather a while back and i always wondered what all the markings on it meant. It's a typical sporter, B.S.A no1 mkIII*, made in 1918, but besides that i have no clue what the other markings mean.
If anyone could give me a bit more history on the rifle it would be appreciated.
Some photos:

 

[buffdog]

.
The other markings are proof marks and Inspection marks. The arrow is a Broad Arrow signifying ownership by the Crown, and the "18" on the barrel is a date - (original barrel.) Some of the proof marks are Military while others are Commercial Proof Marks for testing at Birmingham after it had been sold out of Service, (.303 - Nitro Proof - Crown/BM).