You are not allowed to time yourself at the time, but can analyse your laps recorded on camera and get your lap times this way afterwards. Not sure why would anyone be so intersted in Snetterton, esp with long straights the car will make significat differences.
TVR Cerbera...1m 24sec (I might add a friend was timing be from pit straight) full fuel tank with passenger. Second ever trackday, although think I could go quicker if I could stop my tyres melting!