Ok, it's the right side.. Contact the dealer, there, you bought through, + UK manufacturer,

with your picture, it does not require the resolution I had to find to show cracks 10mm long..


complaining here is not going to bear fruit. ( other than, I could sell you the one I took off)
not much possible resolution from others half way around the globe, .. will agree it's rare.

but selling millions of any thing. 1 in 10000 is not 0 .



you don't have to use a Brompton, crank I took mine off,
and fitted a Swiss made 2 speed, internal gear crankset.

Possible non direct replacements ..

you might get a track crank. or BMX, another single speed,
If the 3 speed then the 1/8" chainring.. if the 6 speed, then a 3/32" thick chainring..

consult, in person, with a bike shop, there, about the compatibility..