Ok, here’s what I tried.
I removed client and shared from eclipse. I deleted the projects from eclipse, leaving the files on the file system.
Then I did a Gradle import for the workspace folder. Note workspace is both the root of the Gradle build and the Eclipse workspace root. The import appeared to proceed, I clicked to keep the existing .project files. Both client and shared were imported, as well as workspace.
Now, when I tried to refresh the child projects I get a different error message, but pointing to the workspace instead:
A project with the name workspace already exists.
It sure does…
Then I tried something different. I moved workspace, client and shared to a different folder, not having workspace as being the eclipse workspace.
This time it appears to have worked, so thanks for putting me on the right track!