Having seen good reports on the Hankooks I managed to source some run flats to replace the disappointing Michelins on the rear axle. The Hankooks are impressively quiet, as comfy as the Michelins and appear to grip as well in a straight line. In snow they were an absolute revelation!
Unfortunately they have made the car really, really nervous, feeling twitchy and positively unsafe on the motorway. I've played around with pressures, which has got rid of the odd "slip then grip" sensation when faced with even the slightest steering movement, but find the stability system cutting in almost every day at very moderate speeds on constant radius curves like motorway slip roads. Overall, I love the silence, and the fact that I am getting more MPG, although that is because I am having to drive more slowly. Cannot recommend these tyres, and can't wait to get rid of them. They have effectively ruined what was a very decent drive, and my wife flatly refuses to drive the car now- it really is that bad.