Thanks Steven. I now have it working now. But it's not as I expected. But it is indeed doing what I want, so I'm happy to leave things as they are.
In Tools I have re-ordered the three apps, with Streamripper in the number one slot, followed by Goldwave and Album Art Downloader.
In Hotkeys I have "Send To: External Application (now playing)" blank. And set up "Send To: External Application (selected files) 1, 2, & 3" to follow the sequence of what I have in Tools.
Using the hotkey for "Send To: External Application (selected files) [1]" does launch Streamripper with the 'now playing' track data being to Streamripper. And Streamripper rips the stream. So all is well.