Got back from viewing the GS430, the only word to describe it is stunning.
The car literally looked and felt like new, absolutely everything is in full working order,
The air con was icy cold with no smells, all electrics are spot on. Whilst it was strange to have the heated seats on with the air con they got nice and warm, steering wheel works fine both rake and reach. The boot doesn't like like it's been used, everything spotless and crucially bone dry!!!
Cambelt done at 104k, auxiliary belt done too. Every old MOT present, a folder full of invoices and bills. It's obvious the previous owners haven't scrimped with the maintenance. Full book pack and 2 keys.
The car drives like new, everything feels as tight as a trampoline.
I'm going to leave a post on the GS forum to see what they say. I told the dealer I'm going to think about it overnight and let him know tomorrow if I'm having it.