Poor ride???

Hi
I have a 2001 4.6 Vogue. I've had it about 6 months and have come to the conclusion that the ride is appaling, to the point it nearly makes me sick. I was under the impression that they are supposed to have a limousine quality ride. I expected it to roll round corners but the compliance of the ride is awful. At slow speed the ride is harsh and dips and bumps all over the place, at high speed you have to really concentrate to keep it on the straight and narrow. Unless the road is billiard board smooth, when it rides like I think it should, it's hopeless. It's on standard 18" wheels and Continental tyres. The suspension was checked at the last service at RR specialist and declared 'nothing wrong mate'. The air suspension goes up and down as it should and there doesn't seem to be any obvious problems.
Are they all like this? I just cannot believe that anyone would put up with this sort of ride quality on a car that would have cost £60+k. Any advice, tips, gratefully received, otherwise it may be appearing in an Auto Trader near you soon!!
Keith S

Have a look at the shocks and suspension bushes for signs of wear/leakage. New shocks start at about £20 each for originals. Suspension bushes are cheap, but a pain to change..need to get them pressed in, unless you go for polybushes.