I've found the correct steering wheel:

http://www.fordonlineparts.co.uk/product/Ford_KA_Leather_steering_wheel_Red%7CSyracuse__with_controls_-_2008_onwards_-_1573500_F1573500-546

I have one without buttons... is the loom for the buttons fitted in all Mk2s? How do you take the steeringwheel off in the first place? (Little hesitant prying with a screwdriver around the airbag to work out where any catches are)

And does anyone know anywhere cheaper to get it?