Well, today I went to get it diagnosed. The H&V problem is diagnosed as being a faulty "Amplifier a/c" part L88650-53010, and guess what - its only £504 or £682 with VAT & fitting.
As to the "Snow/Pwr" switches failing to function they are not even part of the same circuitry.
In the 17 months that I have had the car I have had a new radio/CD fitted under warranty and 5 new wheels begrudgingly fitted free. Oh and 3 tyres wore oddly as the tracking went out - twice.
Am I just unlucky or are all Lexus this prone to failure?
Does anyone know where I might be able to get this part cheaper or perhaps from a scrappy? Or is there some other solution?