I know its about him, OP, selling , on this thread..

but, Mr Arnold, a shopkeeper, chiming in, Bene Sugg: look into the new Efneo GTRO looks good , an internal geared 3 speed ,
so needs no front derailleur ..[ Or bracket needed to fit one.. on telescoping behind the BB folding bikes..]
1:1 low a 28t , overdrive 2nd & 3rd, are effectively a 40 & 50t.. Merry Sales Imports picked it up.

Patterson Metro is also a 1:1 28t low, with a '45t' high...

a cable shifted variant in the niche of a Schlumpf speed drive (which uses a 34t chainring at its minimum, 34, '54')...





....