Whistling sound while driving

When you have accelerated to cruising speed does the noise reduce/stop ?

I'd characterise that as more of a squeak than a whistle. I know that's not much help, but there's more of a mechanical element to it I think. Something caught in the brake shields was my first impression.

Stone caught in the brake pads/discs? Definitely seems related to road speed.

does it change when turning a certain direction?

if so I reckon it's the shield behind disc.

easy to bend back with wheel off.

Its not wind noise, and unlikely some stone stuck in break pads, but it could be break dust shields if they become loose they rub against the disk and make this metallic noise. Have a look around yourself, poke it with a stick.

Then bring it to a mechanic who is willing to drive the car for you and diagnose.

Thanks

If it stops when you brake I'd be looking at a sticking caliper, which is why I asked the OP.

Is there a roof rack?