Does anybody know how to change the date format to UK format?

It's determined by the locale. The default is US English, which uses mm-dd-yyyy. If you go to Customization > Languages and edit yours so that the locale is en-GB, you'll get dd-mm-yyyy.

(I think there's a separate setting too somewhere for overwriting the locale's choice, which you could find by searching in the ACP. But changing the locale is the obvious answer.)

Cheers sorted