[Alchemisty]

Thanks chaps - this is great advice. Picked the car up today, what a machine! Drives more like my old E46 M sport touring than my X5 E70!).

Anyhow on the wheels, got home and popped them all off, greased the flanges (as all were binding a little and not easy to tease off) and tried a front wheel on the rear. Good news is the flange is the same size, hence my plan is to get a full size 19" the same as the front (as you suggest) and use it as a spare for long journeys, if it will stand up in the boot next to the dog cage I'm sorted.

Also great to see the scissor jack I carried for my E70 (from a MkI X5) works perfectly on the X3 too, hence with a spare wheel I'll be sorted.