maybe new cranks from the parts box if i feel the need but not too fussed on fiddling...
If you're looking for a decent cranks, look at the TA'S 50.4BCD one, they can go as big as 64t easily, and there's TA cranks for the moulton, thus should be fine on the Brompton.
If you're looking for a decent cranks, look at the TA'S 50.4BCD one, they can go as big as 64t easily, and there's TA cranks for the moulton, thus should be fine on the Brompton.