Gavin / @glawrie, and MOT fails sucks. This is independent feedback outside of Lexus right?
After I bought mine, Lexus tried to convince me that all of my dampers needed replacing, even tho they were bone dry. Yet they passed an indi's inspection and have been through 2 MOT's since. A good money spinner for Lexus that.
I recall that Lexus Lincoln quoted me around £700 all in for them to change all 4 dampers, so it maybe worth ringing around a few stealers for quotes?
I've had good experiences with RockAuto for parts from the USA but dampers seem to be constantly out of stock.
I vaguely recall someone on the forum using NipponAutoSpares.com for dampers.
Good luck and let us know how you get on.