the thread on one of my handlepost screw holes had worn so that i could push the screw in with my thumb (er, not a very safe situation), so i contacted Dahon UK and they said they'd send a new handlepost to my local bike shop, the bike is a year old. Now here's the frustrating part, i could have easily fitted the handlepost myself but if i did bang goes the warranty rights. i didnt buy it from my local bike shop they said £20 to fit it, i said but i could do it myself, they said 'feel free, but you'll lose your warranty.' They added that if i took it to where i bought it from the work might be done free of charge, but isnt guaranteed.
Now i know there's a 'buy local' brigade out there but for me that doesn't wash. My local bike shop has its own website, selling bikes at special deals, they just didnt have the particular one that i wanted, so for me i can't see any difference that i didnt buy if from them.
So, if anything goes wrong with your Dahon, which is the fault of the product and not the customer, and you still want that warranty cover, its going to cost you.