Just noticed a kind of metallic fluttering noise from my front right wheel, kind of like if you blow out/exhale and wave your hand over the front of your mouth. Is this symptomatic of a dud wheel bearing?

Most likely brakes are glazed. Try a few 60 to 10 MPH hard braking (don't stop and make sure safe to do the hard braking). This usually cleans the pads and discs a treat.

figured out what it was, the front tyre was down to 19psi, not sure how i missed that, anyway all back to normal now.

Aghh i was gonna suggest that but didn't think you would miss that.