Re waiting list – No. I was in a branch of Cycle Surgery in That London’s Famous City of Westminster the other day and they had upwards of 20 Bromptons built up and on the shop floor. Given the other branches they have, there would be 100+ available from stock within a couple of days, at most.
My LBS usually has five to ten built up and on the shop floor in the wilds of Wiltshire.
So, if one of those fits your chosen spec, there’s almost no waiting list.
Granted, if you want something bespoke, colours, etc, then yes, you have to wait for it be built.