What size number plates for a 2012 Outback?

[ShakeyJake]

Hey everyone,

So I'm really enjoying my new Outback so far, I'm only a week in but I'm loving it. I want to put my private plate on my new car, what size plates do I go for? The back is obviously designed for the taller plates that they use in other parts of the world, what UK sizes fit in there? The standard UK size just looks really lost in such a big space. Would a curved one like the Rover 75 plates fit? Or what about another style? What do you guys have? I have tried just measuring it, but it's the curves that are the problem, not the straight length and height?

Thanks!