On a lot of these london transfer questions i don't hear too much about a cab or private driver. I am staying at the The Trafalgar and was thinking of having a car pick us up. There are 3 of us and the prices do not seem too high, around 30 pounds one way total.

Is there a down side to doing this, maybe traffic? We have a noon flt so was thinking of leaving around 8:30.

The site I was looking at was called Just Airports.
Thanks.