Just received my Amplifier back all up and running at a cost of £285 and I also had to pay for the Recorded Delivery of the Amp but the redelivery was in the price.
Absolutely first class people to deal with and I received a report about the reasons for my particular problem and a method of reducing the risk of repetition of this common fault in my unit.
The repairers were Sound and Vision at 284, Leith Walk, Edinburgh tel 0131 5532126 - Internet link below:
http://www.svtservices.co.uk/lexus-mark-levinson-power-amp-repair-service/
Chris who I dealt with suggests that you telephone as some Amps are more problematical and he is happy to advise.
For my own part I am raising some issues with Lexus and what happens next depends on their response.