Hi Ross,
The problem you have. you should ring your lexus dealer where you bought the car, see what they can do and let them know to let head office know, I have common view like others, we should expected the luxury car have better quality and last lot longer than normal rang of Toyota cars.
My car it only had a engine cylinder compression test done by Lexus in North Shore. they find the problem. It is not open engine inspection. Therefor only cost me less than100 $. Anyway I have see news.com 16 Oct. 2014 have latest news for Lexus globe recall 1.75 million and Australia Recall 10,000 cars. Stated mode including all is250 from 2005-2010. You can check online find details and your VIN no. is in recall or not. I'm waiting for receiving a recall letter. meanwhile I just top up oil. I love the car, but also it worries me too. If that helps I am happy.
Good luck, SL Bee