Yeah I was going to say the public transport in london just works, it is the one place in the country where public transport from a travelers point of view is simply efficient.
Getting a car in London is the most pointless waste of money, mine sat unused at works subterranean carpark for a full 12 months before I decided to sell it instead of re-taxing & insuring it. Simply madness if you are central.
Taking a car from Paddington to liverpool street would take you an age, the tube should take you 35-40 minutes (I used to do Paddington to Aldgate east twice daily on the hammersmith & city)
The only faster way is by bike!