A clean visor is a safety item as much as a comfort one, since scratches and haze scatter light and make it harder to judge distance in low sun or at night. Clean a visor with lukewarm water and a soft cloth, and avoid dry wiping, which is what causes most fine scratches in the first place.
Visors are a wear item, not a lifetime part of the helmet, and most riders find a spare on hand is worth having, especially before a long trip.
This kind of workshop sits closer to a design studio than a factory. Colourways, trims and finishes are developed the way a small run of any crafted object would be, with samples, adjustments and a final sign off before anything reaches a rider.
To see the current range built this way, visit full face helmet.
A made to order helmet starts long before any material is cut. Measurements are taken, the intended use of the helmet is discussed, and a rider works with the maker to settle on a shell, lining and finish that suit them specifically, rather than picking from fixed stock sizes.
A helmet workshop in London works on a smaller scale than a mass production line, and that shapes almost everything about how a helmet gets made. Materials are chosen and checked by hand, shells are shaped and finished in small batches, and problems are caught by people who see every stage, not just a sensor on a line.