Hi everyone, I think we have finally found the cause of the noise! When we removed the left front wheel again to replace the brake caliper, we noticed that the wheel hub was sitting a few millimetres out instead of being fully seated in the wheel carrier. This seemed to affect the position of the brake caliper, leaving some play in the assembly. We removed the right front wheel to compare both sides. On the right-hand side, the hub was seated correctly in the carrier, with no gap. We then bought a new wheel hub and bearing and had them fitted by a machine shop. The new hub seated fully in the carrier, just like the one on the right-hand side. The play in the brake caliper assembly also disappeared. After the repair, I drove the car for quite a long distance, and so far, the noise has completely disappeared. My suspicion is that the old hub was not seated correctly, affecting the position of the brake disc relative to the caliper and causing intermittent rubbing or vibration while driving. This would explain why the noise stopped as soon as I lightly applied the brakes and changed when I turned the steering wheel. Before finding this, I had already replaced the front brake discs, pads, caliper pistons and wheel bearings, but none of these repairs had solved the problem. The wheel carrier itself is the only major component on that side that has not been replaced. I'm sharing this in case it helps anyone else experiencing a similar intermittent metallic scraping noise. Thanks to everyone who offered suggestions and advice!