Car behaved on the journey back - actually felt better than it did in the test drive.
Worst I had before was 13 miles into ownership of a car when the gearstick detached itself from the gearbox (old Cortina) - touch wood, around 50 miles now and no hint of any issues I wasn't already aware of.
Just remembered, the drivers side electric mirror doesn't seem to move, though other things I didn't test do work, such as the cruise control, CD player and the door locking button (this didn't work in my last 9-3). Had thought it was way overdue a service, but found evidence of a recent oil change so that was good.
The cat likes it (even though it looks live I've chucked her on the bonnet to take the pic!)

Have a list of jobs to do over time, first being the brake pads/disks which I'm going to try to get done this week sometime.