Yes, they're currently airing Mon-Fri on the Starz Encore Westerns channel, two or three episodes per day. I recorded one a few days ago. My HDMI recorder only records progressive frames, so it had to step down from 1080i to 720p. Still, it's much better quality than I have ever seen for this...
In addition to Stagecoach West, Talking Pictures has been airing The Detectives and Target: The Corruptors for many months now. Perhaps you could prevail upon a Brit friend to record them for you. It would be great if Renown could release dvd sets as they did with Stagecoach West, but...
Regarding Richard Diamond, I corresponded with the folks at Talking Pictures some time ago. They have access to the Four Star catalogue, but this only includes season 4 of Richard Diamond (the NBC season, not the three previous CBS seasons). Of the 26 episodes of season 4, only 12 videotapes...