Sorry to hear you were the victim of a scam - unfortunately there are plenty of scams sites like this out there and Ugg is one of the brands that you'll often find counterfeit goods of. Even though you're unlikely to be able to get your money back, it's really important to report it. Action Fraud is the UK's fraud reporting centre - they collect fraud reports on behalf of the police and you get a crime reference number when you report it.
The site also has useful info about these kinds of scams:
http://www.actionfraud.org.uk/fraud_protection/counterfeit_goods
http://www.actionfraud.org.uk/fraud-az-online-shopping-fraud
http://www.actionfraud.org.uk/report_fraud