Can anyone tell me what this part is ??

The grey box that's bolted to the side of the gear selector.

When I try and start the car the box just clicks/clunks but the car doesn't turn over (fully charged 6 month old battery and new starter)

Click image to enlarge

Click image to enlarge

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Starter inhibitor? To stop you turning engine over unless in Park or Neutral?
Only a guess... 
Had it, loved it!
2007 Vogue SE TDV8
Stornoway Grey / Ivory
Climatic Seats, RSE, AFS, Deployable steps, iPod kit.

I could be wrong, but I think the inhibitor is bolted to the gearbox.

its the unit that holds your key transponder details, EWS unit V8 facelift Range Rover Autobiography 22" wheels.
1976 Harley Davidson Iron Head Sportster

When you put the key in does the steering wheel unlock? I was thinking the battery in the key fob might be flat. Previously..
Vogue SE TD6
Defender 90 2.4
Defender 110 TD5
Vogue 3.5 EFI

Ohh, that doesn't sound good (sounds expensive)

Any idea why it would make a noise and not work?

Contraband wrote:

When you put the key in does the steering wheel unlock? I was thinking the battery in the key fob might be flat.

the unit looks for the transponder chip in the key and if it see's it you will here the ignition lock clunk..if you have a flat battery or even no battery in the key fob it will make no difference to its operation, if you can put the key in the ignition and it turns then its working, does the engine crank over  V8 facelift Range Rover Autobiography 22" wheels.
1976 Harley Davidson Iron Head Sportster

Thank you for your help..

No, the engine doesn't crank at all.

Battery is good (new Bosch last year) + New starter.

When you try and crank the engine all you get when turning the key is a little 'chirp/click' from the mentioned unit.

Sometimes it actually starts first turn of the key, and sometimes you need to turn it 50+ times, then suddenly it will crank and start

It used to do this maybe once a month, but now got to nearly every day..

Could this not be a sticky selector cable not allowing the auto box inhibitor switch into the correct position for starter operation?

I'll have a look tomorrow, but I did try working it back and forth, also tried in 'N' with no luck.

Have a look at this, although you don't have the symtoms listed, lack of lubrication on the bottom end of the cable could affect the inhibitor switch.

http://www.fullfatrr.com/forum/post87201.html#87201