I agree Jon...it does sound like it could be a mis-sold policy. Have you thought about contacting the media? I know that Auto Express have a weekly column where owners the have been messed about (usually by dealers) and it tends to get the issue sorted. I have never seen Lexus appear in there and seeing as they came top in their dealer satisfaction poll, don't think they would like the bad press.
Joe Finnerty is the guy to email
joe_finnerty@dennis.co.uk
Hope it all gets sorted out and nice to know there is another Lexus in Hampshire. I think I saw your car in the parking area in June when I had to pop into the dealership. Looks a very nice car.