hi my name is XXXXX XXXXX i'll be happy to help in any way i can.
sorry to hear of your misfortune :(
sounds like a problem with your drive authorization system.
first thing to try would be a new key, you might get lucky.
beyond that an ignition switch that is beginning to fail.
i recommend having the vehicle scanned by a range rover specialist with a dedicated range rover laptop, should be a straightforward diagnosis
theres not much diagnosis you can do on your own, i'm afraid.
good luck, gary