There are others on this forum that had to purchase a second unlock code because of the 30 day expiration. BMW (not the dealer) would not yield on this. I see you're from New Zealand. Maybe different requirements in different countries? Also, I'm speaking about a purchase in 2013, so maybe there have been changes since then.
I got the unlock codes from alpha Racing Germany, they get these codes from a BMW dealer itself:
*** selling on behalf of Zweirad Huber, D-83567 Unterreit (official BMW Motorrad partner, Germany) ***
Yes I live in New Zealand, having a European HP4 version here (bought it in New Zealand) and I ordered everything from alpha Racing Germany too, but the local BMW dealer is activating these things here - no issue at all.
Still even any US dealer will connect through ISTA/P to the German BMW server - no difference in any country I am aware off so far - but again, USA is different due to EPA since you guys can't use the RCK2 kit for instance with a stock ECU where the European version could...you never know.
But if you source your stuff from the real alpha Racing guys in Germany, no issues at all. These codes are coming on a USB drive actually yes. Alpha said why to me why should they time limited, they are connected to your VIN so up to you when you use them....
I just helped one guy here in the forum to source all these codes and items from Germany over a dealer friend - so if you need anything to the normal price (even without these 19% local tax), just drop me an eMail