The number mentioned above - 500 - is optimistic. I remember expecting reaching 250 per month after a few months, starting with no more than 100.
This quite fits the July-August schedule for my two orders which are numbered in the 1300's. And I would not be surprised if it takes more than that. (Sad indeed, because that will mean having to endure our yearly bike vacation with those old Bromptons again, but not surprised!😀