A Brompton has 1200 component parts that are defined by 120,000 drawings? (@ 2:46 in the video) There are 100 unique, current drawings for every part? I've been in mechanical design engineering and worked in factory production for over 30 years and even allowing for assembly drawings I've never heard of anything so bizarre.
I can appreciate some parts having many defining drawings... not sure what the chap meant, perhaps he meant every angle shown as a drawing. Then parts which get made in several stages will have quite a lot of drawings, showing the details of each stage.