Not sure why anything is lost John, it's a brand new 2020 UX therefore well inside warranty but I don't think that's the issue. Bearing in mind we're commenting from a distance I cannot for one moment think anyone spending this kind of money considers one iota of rust to be acceptable let alone the PDI issue. Personally, I would put in writing your concerns to the dealer and what you expect them to do and by when. Failing that you will return the vehicle and expect to be returned to the same financial position you were in before the transaction. I would also ensure that a copy is sent to Ewan Shepherd at Lexus HQ.