On the face of it, this seems like an unmitigated disaster.
Tony was in my view,the champion of the 450h with over 200,000 mikes on the clock.
For Lexus UK not to support him seems very bad news indeed; perhaps contact with Lexus American colleagues MIGHT YIELD NEWS AS TO HOW THEY DEAL WITH THE PROBLEM?
If the car recently passed the Hybrid Healthcheck, then why does the 12 month warranty not cover the failure ?
It would be helpful to know the cost of the replacement/repair as in my view, if it amounts to significantly less than the cost of a new car it might seem appropriate to effect the repair.
Just my thoughts.
Regards
John