Hi there, I used to do this journey quite a bit by car...if you're leaving around 7 or half 7 you should have a pretty easy drive until you hit embankment, it will probably take you around 1.5 hours, but can be pretty variable unfortunately. An alternative is to get to waterloo , clapham junction or vauxhall and take the (slow) train from there...it's a bit less hassle than paddington (and cheaper) if you're prepared to spend an extra 30 mins on the train.