Hi Mel .. The wee Milbro Diana model 16 was one of the first air rifles I ever fired when I was about 11 years old... That and the slightly more substantial Model 23 with the solid steel barrel.
I picked up one fairly recently which needs a bit of a refurb but it's basically in not bad nick.

The cocking lever, breech detente mechanism is quite ingenious I think and suits the wee gun perfectly .. I think mine is of 1963 manufacture ... As you may know four numbers are usually punched/ teeped into the top part of the butt above the 'ribs', but don't always survive over the years if the gun has been roughly stood on it's end, frequently.
Hope you enjoy rekindling fond memories with it.

Missed you at the June Bash btw.
A' the Best,
Graeme