Hi Just wondering if anyone has any information on a 2007 range Rover sports V8 diesel.
if the engine overheats is there some sort of safety switch or sensor that would stop the vehicle from starting until it was fixed?

 

There is not. Computer will try to protect the motor from damage by entering limp mode. Once it has cooled off however that will go away until it gets hot again.

It's possible the overheat caused internal damage and that is why it won't start currently.