R75,
As Rodders suggested, I think you should test drive the GS series, coming from the Rover 75, this would probably be a better choice than the IS series, also as the GS series has been around much longer, you would have much less problems, though I am not sure of the paint on them.
In any case test drive both the IS and GS and see what you fancy.
As has been mentioned by others the IS series from 2002 have most of the teeting problems sorted apart from paint.
Let us know what you go for.