I did get an Astra 960 cylinder stop from Valley Guns about 3-1/2 years ago- the only place to have one after a comprehensive search.
Here was the tagline in the archive email and the beginning of the message:
From: "Jack Herbst" <
[email protected]>
Kirby,
We have the following;
Astra 960 cyl stop
Look them up, give them a shout.
Swing and a hit.
Kirby