Currently Being ModeratedMay 21, 2013 8:59 AM (in response to glynnwebb)
It seems that all the other device show the correct time, date and region. I would recommend checking the time zone of the Mac itself. Below, I have included and article that may resolve the issue with events showing an hour off.
Also, check your events on iCloud.com to make sure the behavior has is not being experienced on there as well.
Hope this helps.