Did the dealer sort all of this for you? I have a private plate which is only 5 characters long so maybe this is something I should ask them to sort for me...
No, I sorted the plate thing as follows:
375mm 'Italian' plinth from EB Spares - £12 plus p&p. Had to come from Italy and took a week
350mm plate from Craigsplates - I think this was about £22 plus p&p. The plate can be as little as 342mm (without Euroflash or badge) with 5 characters from memory, but since the plinth is 375mm, the 350mm plate is as close as I could find without getting into silly money territory with a custom plate. All this takes a fair bit of time, so don't leave it too late.
But it doesn't all end there!
The narrower plate has circular section protruding from the rear that is designed to fit into the tow bar socket hole on the offside of the UK cars. The problem with this is that it pushes the short plinth as far right as the standard UK plinth, which still covers the scoop in the bumper and doesn't look right. So, the protrusion on the back of the plinth has to be cut off to allow the plinth to be fitted centrally, next to the grille.
But even that isn't the whole story!
Barry Z is correct in that my car came from the factory with the plinth already fitted (photos of my car with the wrapping on are on another thread). Both the long and the short plinth are secured to the bumper with 4 screws - 2 in a vertical line on the left hand end and then two staggered on the right hand end. This means that, if, like me, you want a short plate centrally mounted, the shorter plinth can be fixed into the 2 left hand holes, but the right hand holes from the factory are then visible as they are not covered by the shorter plate.
The only way to resolve this is to have the holes filled and sprayed - not ideal on a new car, but that's the choice. As I had been discussing the short plinth thing with the dealer for weeks and had made it clear what I wanted, he very kindly arranged for this to be done by the body shop before I collected FOC to me (I must have left too much money on the table when I negotiated my deal!!).
The good news is that the Comp Red is extremely easy to match and blend according to the body shop and I now have a handy tin of ready mixed paint for the inevitable stone chips. The detailer I took it to was happy enough with the spray and the repair is invisible. Despite all the aggro, I figure it is worth it.
So as Barry says, when you order, ask them to ensure the front number plinth is left off. Indeed, my dealer thought that the next batch of cars may be coming without the UK plinth factory fitted, so Alfajunky, Andy and others that are due to get their cars in the next couple of weeks should be able to confirm.
There is a whole thread on this on the Giulia Forum called 'Smaller Front Number Plate' and as I haven't had an Alfa before, this offset front number plate thing was completely new to me, so my thanks have to go to @Scotital, who clearly is the guru/anorak on the subject!