Unless I'm mistaken, that's already the shorter of the two alternative screens that BMW sell so the only other BMW option is the little black one that comes with the Sport.
Either BMW or wait for one to appear on eBay I suspect.
If you mean the small black screen that just covers the clocks you might have to buy new. I keep an eye on EBay and I think I’ve only seen one come up for sale in the last 12 months. I’ve got one and it’s similar to going totally naked in terms of reduced noise and buffeting - go any bigger and the noise can be horrendous. I tried the Puig and over 50 it was unpleasant.
If you mean the small black screen that just covers the clocks you might have to buy new. I keep an eye on EBay and I think I’ve only seen one come up for sale in the last 12 months.