Fan Noisy WBX Alternator - Alternatives?

[cobblers]

I've had 4 or 5 2.1 WBX engined vans, and all but one of them has made a hell of a lot of fan noise, to the point where it's actually just as loud as the rest of the engine. 
My current Doka is the worst of them all. Alternator is an OE Bosch. Span it up with a drill and the bearings etc seem OK, it's just the fan that makes an absolute racket.

Has anyone tried the "modern" alternatives sold by SHC with an internal fan? Looks to be similar to one off a merc A class, there's a seller on ebay selling unbranded internal fan upgrades for long snout diesel applications.
I've spent a bit of time in parts catalogues looking for something but not come up with owt. Are they all like this?

[maxstu]

My DJ alternator has always been squeaky. Changed to a new belt. Still the same. Changed alternator. Same. Took and alternator from a running and known DG1.9. Still squeaky. But not on the DG?

No idea. I live with it. But recently my dash charge light flickers when l put the engine under load. For instance under swift acceleration (ha!) or steep hills? Yet fine when cruising at road speeds.

[Stesaw]

Scuff up with pulleys with some sandpaper. If they've smoothed out its possible it might slip.

[maxstu]

Yeah. I did that too. Still a squeak here and there!

[Mocki]

I took the water pump pulley off and scuffed it up ( well put it in the angle grinder and made it un shiney with Emory paper )turns out it wasn’t the alternator at all ….

[cobblers]

They pulleys were a bit polished, I've always been wary of tightening a WBX aux belt too tight after seeing a couple of cracked crankcases, so I'll err on the side of caution. I stuck the pulleys in the media blaster at work which did help stop slipping etc, but the noise is definitely just the fan. It's fine at idle, but at 3000RPM etc it makes such a whirr.