This only changes the dates in the results sets. If you are looking at the Summary pages when you first log in they are hardcoded with the US format. You will need to change the XML to show the non-US format.
on whatever page you are on append ?showsource=1
You will see at the bottom in the XML window that there are lines like: …………fieldformat "Last Update"=strftime('Last Update', "%m/%d/%Y %T")
Modify them to say "%d/%m/%Y %T" and you should be good.
You can change the search/XML in the Manager--> User interface --> Views to the format you want.