Have found it: change m/d/Y to d/m/Y on
Line 185 of admin_cms/contenthistory_results.php
echo date("d/m/Y", ($row_WADAcontenthistory['HistoryDate']));
(for the benefit of others)
Might I suggets somethig for a future development? Have a 'Content Active' checkbox, which would enable the super-admin to create loads of pages in readiness - but mark them as inctive so they aren't displayed. The ordinary admin (the client) could then add extra pages using the pre-made inactive ones simply by marking them as 'active'; this would provide some extra flexibilityand stop the client pestering!!