Thank you to those who replied to my question about the 'protection' plate(s).
The plates have been installed by the Lexus dealer. I also have a Stop Lock Pro Elite taking up space in my top of the range RX450h, no doubt offering opportunities for damage to the interior over time. In essence, I have two sticking plasters that offer nothing, other than delay and minor inconvenience to would-be car thieves.
Lexus Customer Relations advise it has taken seven years for thieves to discover the opportunity to steal Generation 4 cars in seconds. Apparently senior management are aware of the '... shocking impact on customers, insurance companies and Lexus'. Clearly, customers will pay the price for the theft of their Lexus cars and the increase in insurance costs. What impact the issue will have on sales of new Lexus vehicles and second-hand values will remain to be seen? I anticipate this is the sole issue that will provoke any further action from Lexus/Toyota.
However, the Generation 5 RX is manufactured to a different global architecture so they will not be targeted in the same way. So that's all right then ... .