I think the Geo is office is in Wong Chuk Hang, which does make things inconvenient.
There's an HSBC Branch and a Premier Centre in Aberdeen. Surely you get a lunch break?
Your options sound pretty limited, so you're going to have to pay for the convenience.
Ask your bank about your maximum daily withdrawal overseas (I remember you could set it as high as 40k HKD for HSBC Premier). Bring HKD cash for the remainder and change it in HK airport or when you get to the UK. This will minimize the hit you're going to take.
Otherwise, Western Union to yourself (assuming there's one you can reach nearby)
Too late - he flew last Friday.
Yep, already here and sorted everything out via citibank. Would have cost me around 3000$ if i went to travelex