Maybe I should clarify: this bus is not Enviro 400 MMC.
Yep, I know it has got a MMC body and it looks a MMC. But no, underneath the body, it is still a traditional Enviro 400 chassis.
There are multiple sources online stating the bus is a traditional Enviro 400, and I could not find any sources suggesting the bus as MMC.
Therefore it is wise to say this is a unique designed bus for Hong Kong, so as whistlehead said above, it is a very different bus to the Enviro 400 MMC in the UK.
Despite saying that, I think this bus uses a rollblind to "simulate" the electric display anyway, so you can always make your own display with the aid of photoshop or paint.net or whatever you use.