Air Con: Noisy interior blower fan

[skiffy]

Hi all,

I went and looked at a 55 plate XC90 last night. Pretty much all good but one thing really struck me (and I've had an XC90 before so I know it's not normal). On the test drive I set the AC to min to test it. The blower wound up to max and it was really loud, sounded like the engine, so not squeeling or anything just humming really loud like an engine. I've done some googling and at a lot of the time it sounds like it could be debris in the blower causing it to be unbalanced. I read on another thread here that this is easy to clear by accessing via a removable panel under the windscreen in the engine bay. Can anyone give some specific guidance on how to do this as I wouldn't mind checking it out before parting with any cash. I don't want to put up with noise like that!.

Cheers.