Looks like 10miles is my best distance comparing to other people's times but I'm guessing it's not a common race distance for most of us. I ran two last year but they're not until October and December and I'm away during the October one.
Katy, what I would do is start out at 7:30/mi as you know you can do 47mins. By trying to 'bank' time you're running well above your lactate threshold and the lactate will build up too quickly and slow you down. So it's counter productive. Run the first half at 7:30 then step up to 7:15 for the second half. Then really push at the last km.
Although the only 10ks I've done were hilly trail so I just go on effort and rely on the downhill to recover slightly, trying for 8:00/mi in general.