Just got back from Gamestation after trading in my premium. You can keep your hard drive. They reduced the trade in value by £32. When you bring back the hard drive they will credit you the £32 back.
The staff were really helpful. I only want to transfer my game saves but don't have a memory card. They were going to give me a used memory card to take home and transfer the saves. Unfortunately, they had no used ones in stock. I have a Samsung LCD and to be honest there is not much difference bewtween HDMI and VGA on the dashboard, not played any games yet. It has the same fan noise as my previous 360, not bad because my old console was fairly quiet. The fans are marked 'DC Brushless' ( the same as my old premium.) DVD drive is a BENQ.