The now discontinued Tikit rolled on its front wheel, because they had designed the handlebar mast fit, a button on it,

Into a clip on the frame tube , locking the wheel straight,

...But the fork is Brompton like 74 MM and front hub motors out there are all 100mm axle width..

Some have adopted the mid drive Bosch motors most go with hub drive .. and if a 406 wheel odds are the fork is 10cm.