You shouldn't have any problems Exiled, my IS 220d has broken down in the South East, the South West & the Midlands (twice) & each time the dealers have been very helpful although obviously the inconvenience is a pain. It's the car that's the problem, not the dealers.
Thank goodness that Lexus dealers have a good reputation on the whole, let's hope that Lexus manage to get to the bottom of all of the problems before all the drivers lose their patience & start to vote with their feet....