When logged into Anaplan can you click Help>About. This dialog will display which locale Anaplan is picking up from your browser, it should be en-gb to use the UK date format.
There is no way to directly change the locale in Anaplan itself. However the locale can be specified if you're using Anaplan Connect to trigger your imports by using the '-locale' command. This can be specifed in your batch or shell script in the set Command line like in the following example:
set Command=.\AnaplanClient.bat -locale en_GB %Credentials% -workspace %WorkspaceId% -model %ModelId% %Operation%
It's also worth noting that our next release will include a new feature that allows you to specify a date format when you're importing date values.
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