The Mk VI telescope was introduced in 1926, superseded by the Scout Regiment in 1939 but still in service in WW2.
It has 2 separate eyepieces, 'Low' power at 15x, and 'High' at 30x.
I prefere the Low-one. Whichever one was not in use, sat in the additional miniature case attached to the sling strap. (The sling is missing)
The following text is engraved: " Tel. Sig. MK VI OS 717 GA"