Thanks. I wasn't aware that the only difference between generate and publish was the location. (I imagined that publishing compresses files etc. etc.). I have the output from both generate and publish going to local folders, and I can tell by the time-stamp that I am comparing the right files but …
… I think I may have solved a couple of problems that have ben plaguing this particular project (starting with seeing two identically named topics when I search for a topic to link to). It looks like I was dragging an earlier project folder and mistakenly dropped it on top of the current folder for the project. Thus I had a copy of the entire (earlier) project inside the contents folder of the (current) project. Thus an exercise to link went looking for the topic in the tep-level Contents folder and found it at two levels. In the meantime, some additions were being made (by me) to the embedded earlier version annd the current version (without realising). I've now ditched the embebdded version, updated content where necessary and fixed broken links (i.e. links to the wrongly embedded project). Not only has this fixed the topic-duplication issue, but it's fixed the generate–publish inconsistency issue. What a palaver … thanks to a buggered drag-and-drop!