On it's sixth day it started running very roughly, and then just refused to start. The dealer towed it away and took it to bits. One of the injectors had gone and it was going to take them over a week to fix that. But they wouldn't know if anything else was busted until they'd done the injector first. So they very kindly offered me a full refund.
I would have persevered with the car but bits of the trim fell off, the fuel filter needed changing and it had no service history...so I cut it loose.