Disco 3 (LR3) Engine scraping noise...help!

Over the past 24 - 48hrs my D3 06 plate has developed a scraping noise which seems to be related to revs . It's most noticeable coming from the off side section of the engine inside/above the wheel arch area. It sounds likes a whirring/scraping noise as if a bearing is dry or some kind of pump isn't running right. I'm totally new to the D3 having only just upgraded from a 300tdi so don't know the engine at all.
I've uploaded a video at idle which hopefully sheds some light on the noise as these things are often difficult to explain in text.

I haven't had the car that long, maybe 3 months. About 2 weeks after it was bought the alternator packed up which was repaired by the secondhand dealer. I'm wondering if it could be related to that as it's in that kind of area.

Can anyone shed any light on possible issues to look at?

Hopefully the video isn't a total waste of time:

Thats going to be hard to diagnose via a video, I would remove the large top pipe (jub clip and an 8mm headed bolt) then cover the large pipe opening on the passenger side, pop off the top fan shroud then get looking /feeling/tugging and see if you can see/feel whats what.
Pop the fan belt off and start the car if theres no noise that awesome news as you then know its one of the accessories alt/water pump/belt tensioner etc, if the noise is still there stop the car and dont restart it until youve had the cam belt tensioner looked at.

Unlike most modern cars once you get over the siht that looks scary part its actually quite easy to get at all the front end gear.
The proper ebay viscous fan spanners are worth their weight in gold, 20 quid Iirc.