There's a lot of brands / retailers putting together cheap folding bikes from generic parts which I assume originate from the far east. It seems a little odd that, given the general compatibility between these standardized parts that I can't find anywhere in the UK that sells them individually. Every so often various pieces come up on ebay. . . but surely there must be a way to locate a source of this stuff. Perhaps there's more available in some parts of Europe; I'll see if I can find anything on the Netherlandic ebay.
But for instance, if someone breaks the stem on their 3 year old downtube mini, that part isn't available on the downtube website anymore. . . perhaps Yan still stocks old components but doesn't list them on the site? There's a zillion brands of folders that use the quill stem/handlepost design, it'd be extremely handy to be able to find a source of quill stems/handleposts so that one could tailor the angle, latch type etc. if one wanted to, or simply replace a broken / worn part.