Fast Commuter Bike (Max £500)

Hi All

I am looking for a fast commuter bike with a maximum budget of £500. My journey is 8 miles all on road. Not wanting anything with front suspension, wanting to keep the bike as light as possible to ensure fast speed.

Lookinga at the Trek Valencia or maybe Marin Muirwoods. Any comments or other suggestions.

Oh,.would prefer 700cc wheels and clipless pedals but not absolute necessary.

Thanks.