Should still make a motoring whirring noise even if the lock hasn't engaged.
If its not making the noise, chances are it's the steering column that has failed and it's that which is stopping the car starting. Sounds odd but it is part of the immobiliser system. Most of the time it fails, the lock fails in the off position.
There are people who say they started the car by wiring up the steering lock to the interior light, or pulling and refitting a fuse, but that only works if the key is still good and recognised by the immobiliser. Mine wasn't so can't confirm or deny this trick on my car.
Apparently the ECU is a plug and play affair, no marrying needed but again, I don't trust a lot of people unless they've proved themselves or my experience backs up their claims.
Have a look here first:
I went to take our L322 2006 Range Rover on a beach trip a few weeks ago and found the steering column failed in the locked position. Since I'm not keen on spending $1000 on a used column that may break again, I tried all the tricks I found online. I drilled and oiled the column with no luck...
www.landyzone.co.uk