Sounds like you gave in a bit easy there pugwash! I would have used the small claim court service at www.moneyclaim.gov.uk to get them to pay up (you pay a £30 court fee up front by credit card which gets refunded when you win).
I am currently trying to change my tyres after the inner rim wear problem on the front wheels. The dealership will say they will only do the modification once new tyres are on. I haven't been too impressed with the Pirelli P6000's which came with the car and they don't have the rim protecting edge for my alloys. They're pretty noisy too.
I am trying to find out if I can fit a higher profile tyre to try and improve the ride quality a little. Currently the tyres are 215/45/R17W, perhaps increase it to a 50 or 55 as there looks like there is a lot of clearance in the wheelarch. I have emailed Fiat for their advice (not sure how much that will be worth!) and have asked a couple of tyre suppliers. Blackcircles say I might need to get a narrower tyre.
Will post any info I get back, I'm sure those of us on 17's would be interested in improving the ride a little.
Fiat Stilo Abarth 3dr. Loden Green, Beige Leather, Sky Window, Cold Climate Pack, 17" Alloys, CD Changer, 260w 8 Speaker Stereo.