Bloody nightmare to find. It is illegal to use a tinted visor on public roads in the nanny state.
BMW Motorrad UK will not sell you one even althou every where on the continent BMW Motorrad will.
The whole thing is very frustrating. I have been trying for months to solve this issue as I ware glasses and in the sun the glare is very annoying.
Had I known this before hand I would not have bought the BMW GS Carbon helmet in the first place.