You can change your default currency, timezone and Buyer's Premium within the Auctioneer settings. Click here to find out how to access your auctioneer settings

Once you are editing the auctioneer, go to the Main Settings tab and to find the following fields: 

Once you have made any changes, click Save Auctioneer at the top of the screen. Once these changes have been made, any future auctions created will use the newly set defaults for currency, timezone and Buyer's Premium. Please note that any existing auctions will not use these new defaults and should be changed manually as required. As usual these can still be edited per auction as required.