I know it can sometimes be a pain calling a dealership and booking a car in but I don’t understand why someone would buy approved used from a Lexus dealership, with all the peace of mind and customer services backup that comes with this, and then suffer a fault and attempt to self-diagnose on the internet. Call them, explain the noise, send the clip too if possible, tell them you aren’t happy and you’d like it fixed please. Take it in and collect it when it’s fixed. No point buying in this way and not using the dealership to diagnose and fix.