Hi Jason & Natalie
Welcome to Hong Kong.
Unfortunately there is no such thing as a "guest of permit holder" access, but don't worry there will be Nordmann's Greenshanks around into June.
The best option before your permit arrives is to join a HKBWS outing to Mai Po - check the event calendar on this website.
NB on high tides Nordmann's will also come onto some of the ponds inside the reserve.
Cheers
Mike
Mike KilburnVice Chairman, HKBWSChairman, Conservation Committee