Hi Mickey
Absolutely no help from Lexus. They came out with me but advised "bring it back if it gets worse or you break down". !!!!!!!
I contacted Toyota to ask if they would interrogate worldwide service records. Again, no dice and a sweet girl from customer services referred me back to my dealership (but you are welcome to take the car elsewhere she said!!!).
Good news is I've sorted it but I can't say if it'll work for you, obviously. A good friend who works with performance cars took it out when I mentioned it. He brought it back after 10 minutes and invited me to check it out. He encouraged me to drive "robustly" and guess what noise gone. He told me that he had thrashed the a*se of the thing, using kick down brutally and ignoring the noise when it occurred. We have concluded that my driving style was too gentle and allowed oil ways, valves etc to gum up. I now give the car a little wellie now and again and so far so good.
Hope it helps