Rock ola 454 , top or number glass.

Hi Guys, newbie here thats been recommended to this great forum.
I am searching for the top glass for my 454 which was missing when I bought it. This is the one with the number / letter selections on it. I have tried the main dealers all over , without luck but am now hoping that someone on here maybe knows of one available . Have sorted a lot of issues with this machine but can't solve this problem ! Help please ? Regards Maurice Green . Uk