Many thanks for your answer.
We run macros at the moment that give us the information. The user does indeed have to download all logs for all their found caches in GSAK. The macro then compares the current user's "Found it" log with the previous "Found it" log and reports the difference.
I was under the impression that Project-GC held logs for caches? Perhaps my impression be wrong.
Many thanks, once again, for looking into this quickly :-)