Running a report based in Melbourne I would like to default to a filter for "Today".
Yellowfin reverts back to the UTC and for a part of the day sees "Today" as yesterday, until the UTC clicks past midnight.
For example 9am 11/5/15 in Melbourne the Today filter returns UTC time of 11pm 10/5/15.
Is there a way to overcome this issue.
yes there is, you've got to use a Timezone Converter, so please follow this link and read the forum post that describes how to use a timezone converter.
In summary all you've got to do is to go to step 2 of the view builder and apply the Timezone Converter to the column you want to use as the filter, and set it to the timezone of the database (in your case, UTC). Then make sure that you have set the timezone for the user(s) using the User management tool
I hope that helps your report, if there are any further questions or issues please let us know.