I tried once yesterday and also my girlfriend tried same thing "automatic".I have 1.5mbps at the moment which i just wanted to have for a few months,i just wanted to have the 3mbit to see the differences and cause of the same usuage allowance i was going to downgrade and save £156.
I am going to try later and get it one more time,pointing them to this website,if they say no i shall downgrade to silver.I wonder if i will then end up with 2 mbit,more likely 750 kbps