It was mostly just a press event. He was told not to go all out, and he was nowhere near the limit. He was on slow tires and wasn't set up for the high speed straights. The reason he went slow- the circuit isn't safe enough for an F1 car's full potential. He was specifically told to go slow so they could take pictures and better show the car off to the crowd.
Top Gear did a blog-
http://www.topgear.com/blogs/motorsp...ick-have-gone/
An F1 car could go out there and set a record that would probably never be broken except by another F1 car, but I don't think it would be safe.
"Right, let's stop all this cack about ultimate lap times here and now. A modern F1 car would be simply lethal on the 'ring; it does not have the ground clearance to deal with the circuit's numerous bumps and dips.
Even if the car's ride height was increased the aerodynamic effect of all the wings and things would decrease significantly. It would be undriveable."