London Parking

[montypython]

It's a long time since I drove into central London, but I do remember how bad it could be.
But in these days of congestion control what's my chances of driving into the centre of London (from the M23) and finding parking to do a few hours sightseeing. And what would be the best route to take. It would be on a weekday morning, probably getting to the M25 at around 11:00am.
I've thought of parking on the outskirts and to take tube/bus but with 5 adults and 2 kids, I'm not sure I want to do that.
So help me out guys