:eerrrmm: Possibly. If you're reversing into your drive the probability is that your tyres will be warm, so if the noise only happens when reversing cold, it shouldn't happen if you are reversing after driving home. :D
Thank you all for your help. I am almost no longer a Lexus owner, soon to have my beloved Camry back. I must say that I'm very impressed with the way that my local dealer has handle this problem and would recommend them any time.