Spoke to the dealer and they said the disc will not work in my particular car. When I enquired as to what numbers on the disc would work in my car, they could not tell me - only the Lexus part number that I would need to order which was PZ485-L01EU-06 which I don't think appears anywhere on the actual disc, so it looks like I accept the current version of the disc in my car, or pay around £270 at a Lexus dealer!