Agree, photo's of the rifle would be helpful, but on the basis of the Z in the serial number, if Stratton is correct, it would relate either to a BSA or RSAF Enfield produced SMLE dating from WW1 or just before. A Z prefix is associated with the following production years: RSAF - 1912, 1915, 1916, 1917, & 1918; BSA - 1915 & 1916.

Hope this helps a little.