L322 Alternators - clutch or no clutch!?

[shentodj]

My 2009 L322 5.0 s/c needs new alternator.

I got one from Rimmer Bros, but when garage rand and told me that the one currently on car has a clutch mechanism on the pulley.
The one from Rimmer Bros doesn't have a clutch.
Rimmers have checked and they don't have another listed. They've agreed a return no problem. Never had anything other then great service.
So next I tried Euro carparts; they checked the one they have listed for my car and again it doesn't have a clutch mechanism.
So this morning I've been on phone to Land Rover main dealers and I'm waiting to here back.

Questions:
Have all 5.0 s/c alternators have clutches?
Anyone replaced one recently, if so where did you source it please?
Anyone replaced a clutched alternator with one without a clutch?
What's the general technical assessment - garage says it will work - can I replace clutched with non-clutched?

FYI: diff prices. Rimmer/Eurocarparts less than £200. Land Rover part = £841.

Advice gratefully received.
Shentodj