Thanks, Przemek for your thoughtful comments. I agree with most of what you say and will consider ways to implement the suggestions. Here are my current responses to some of the points:
1. Deletions -- I hadn't looked at what happens when a quiz is deleted at all and had assumed that the built-in function in the template did all of this. It doesn't, so I'll have to build that in.
2. Concerning the 'unneeded' final set-up screen. This is there because the hotpot.php program 'wants' to write to the screen once it has finished the processing. I'll see if there is someway to make it do this silently.
3. To have something recorded in the hotpot_events file when a quiz is started opens up a huge can of worms although I'd like to see this in a future version. If every entry in hotpot_events is an individual attempt, it makes the reporting of results straighforward. If some records have to be skipped when results are displayed, or displayed in a different fashion, things become messy. It would have to be designed so that the score and endtime is added to the already established record. I'll have to give this a think.
4. Pop-up windows present a challenge since the data needs to be written back to the original window. The pop-up would have to contain hidden frames with the javscript for sending the report since there is always the chance that the student might close the original Moodle window. It might be doable, though.
5. Starttime is currently determined by the Hot Pot application, not by my code, so is the time that actual activity starts rather than when the window was opened. Arguments could be made both ways, I suppose, as to which starting time was most desirable.