As I understand it right now, there is not truly a “batch”, I think that is just a translation error. As I understand it they simply made all they can make before the holiday and will make the rest when the factory opens back up.
So far as I know we have not sold out of the GB lights yet, although I am not sure how many are left.
As long as the promo code works when checking out, the price is in effect. He will disable the code when the GB is over. When that will be I simply can’t say at this point.
I think it is the other way around IIRC, DHL handles the international part and UPS will sometimes deliver to your door. From what I remember DHL is bigger then UPS internationally. Could be wrong though.
UPS operate more airplanes and carry alot of air cargo for others, probably including DHL. Though I’d expect the carrier to vary between routes (for example HK to US might fly UPS while HK to Europe might fly DHL) and over time as the airlines adjust their fleets and schedules, and the couriers negotiate and renegotiate contracts.