I believe you use YaST (Yet another System Tool)
to control this. Under Network Services, you'll find NTP Configuration. As far as changing the calendar to UK rather than US format, I'm guessing that this can also be done somewhere in YaST, but since I don't use SuSE, I'm not totally certain about this. For programs such as OpenOffice.org, go to Tools - Options - Language Settings - Languages, and then under "Language of User Interface" select "English UK" and under "Locale" select whatever your locale is (for me it's English Canada). To do this, you may need an OpenOffice.org English British Language Pack installed (which on my system is openoffice.org-l10n-en-gb -- not really sure what it is on SuSE, though).