The other thing you might like to do is take off the upper rear handguard (the small one - lift the rear sight up to the vertical posiiton to get it out of the way then pry the handguard up carefully it is held in place by two springclips) and look under it at the barrel this is often covered with marks - proof marks (certifying the quality. Originally these would all have matched - often when rifles have been repaired or FTR'd (Factory thorough refinished) these do not match or have been renumbered to match. On the rear of the bolt handle, the receiver, the barrel knox form, the underside of the rear sight, the bayonet boss (on the front sight protector) and perhaps if you are lucky impressed into the foreend just behind where the front sight protector fits, you will find serial numbers. This will likley contain the rifle's mark Sht L E MkIII or Sht L E MkIII* etc and the manufacturer.

The key to identifying it is to be found on the 'wrist' of the rifle (between the wooden buttstock and the fore-end) - it is part of the receiver.