OK, my MBP has started making a crackly sort of sound on boot-up/resumption from sleep. I have established that it's definitely not the speakers (mute has no effect) or the optical drive (it's empty), so I can only assume it's the hard disk.

After a while it stops, so I can only assume it's only doing it under intense reading/writing.

Please tell my my Hard Drive isn't on the way out already...

If it stops after a while, then I suspect it isn't the hard drive.

How old is the MBP? It could be a dry joint or something around the sound chip and where it connects to the speakers. As it warms up, the contact gets better and it stops crackling.

Without observing it, it isn't easy to diagnose, but that would be a best-guess with what you've said so far.

Is there an Apple Store in your area? It might be worth getting an appointment and taking it in. Not an option for me, I need to drive through 4 countries and take a ferry to get to my nearest Apple Store...

Nearest Apple store is Exeter, some 100 miles away, not really an option.

And the Macbook is not even 2 months old.

Then you'll probably need to phone Apple and arrange for collect-and-return...

God damn it.

You're not alone, apparently (< clicky)

EDIT: and here too