I have the same problem with my 05 plate is200,
went in for service and asked them to find the noise and what caused it,so they told me it was the rear brakes lol,any way after some debating with the fitter cos they are not mechanics any more are they.they played around with the front caliper and striped it cleaned umm any way the noise went for a while but then came back and asked toyota garage if they did the other front one which they said no and now the brake pedal is spongy and this was nothing to do with them lol. so what to do next because some times it sounds dreadful and every one looks at you.
ANY ONE?????????????????
Cheers
Andy.
Best way to describe the noise is, as though the disc back plate dust cover is rubbing on the disc itself (metalic noise)