Brake delay as the chain tensioner moves up ?
I note: didnt take out, links [half link] to push it up to be tensioned on the bottom ,
and so the spring only kicks in winding the tensioner when you fold it..
You are obviously a flatlander .. in Tyneside.
Weight in the front bag makes the low trail handling better .. But to each their own... YMMV.
I believe they used https://www.sram.com/sram/urban/products/automatix
And you are right, for safety reason, front brake should be there. Folding is the same, mod the hub to fit the frame.
Moulton has something similar. I wonder how well the belt drive works.