My 07 RX400 came with a DVD covering the whole of Europe. I bought a DVD of Ebay that is one of a set of 4, covering the UK. It went in just fine and has removed the block on entering a destination when moving.
Just make sure it is an original Lexus disk and up to date.
Apparently people in other parts of Europe buy a full 4 disk set, keep the one they want and sell off the others.