Hello, me again.
Sorry, I seem to have found a bug in 4.0.10 ?
If I select Member / User Galleries (Odd it's called Member Galleries in the category list but User Galleries when you get there but that's not my issue, just an inconsistency).
The default Sorting is Sort By: Total Images and Order: Descending.
If I change this to Sort By: Member Name and Order: Ascending and click GO, I do indeed get a set of pages listed by member name in A-Z order as expected.
However, this only seems to be correct on the first page. If I click page 2, the sort reverts to Sort By: Total Images and Order: Descending, so we can only ever find those members galleries whose name starts with A.
I did try searching for this issue before posting it but could not find it, however if it has been mentioned before please merge this with that topic.