Hi guys I dont know if this helps but I bought my Lex gs300 Sport mk1 1997 plate this year with just a grey third key and could not even unlock boot or glove box when dash button was depressed, anyway I went to Lexus Birmingham who charged me around £150 for a new master key as I pressed the button lock just to right of footwell while I was messing with car. I also got for around 100 a new transponder, I did not have anything else when I bought the car apart from one transponder and grey key they took details from the chassis number, engine number and registration reprogrammed key and alarm so now I have a new master key and transponder and my spare key and transponder that all work. lexus should be able to do everything for you for just over a couple of hundred.
If you have any more qs just PM me.
Cheers Buddy
I'm going to Lexus Nottingham on thursdayI'll ask about that.
Thank you
Regards Craig.