Most visitors online was 1660 , on 12 Dec 2020
I've got serials on 32 of them, and so far only 4 have been platinum - nos. 1, 2, 246, and 509. 1 & 2 are Fred and George's personal watches, so I don't think they count.
If 2 in every 30 are platinum, then 40-45 were made. (The exact number would be 43 out of 650.) I suspect in reality, the number was closer to 20 or 30, since they struggled to sell them .
Others probably have more data on the 50th Anniversary watches. I've only been collecting serials on the Verithin series for 5 years, and others have been at it for longer.
Checking your case serial, I see that you've got No. 246.