Wow - was it a particularly hilly course Tom? Looking at 2 local race results, 46 mins would put you at 32% of the way down the field in one, and 57% of the way down the other one (pancake flat), but your position is in the top 16%, which makes your time look even better.
I guess the thing to do is just go for it and push it out a bit more. The worst that can happen is you overcook it and suffer and fade towards the end. To run a 10k really well, you have to be right on your limit, and by definition that means sometimes you will get it wrong.