Should have said it in the OP, I did change company after a bit of comparison site shopping. I do every year, apart from once a few years ago, where my renewal really was the cheapest deal.
I'm aware that the car I'm driving isn't going to be the cheapest to run and insure, but there's no way I'd be seen dead in a Micra. My car is a group 15, but the point is that my insurance is as expensive now as it was 2 years ago, when I was 2 years younger and had 2 years less no claims. Talking to others I know, this seems to be a common theme.