We've now managed to sort out the next phase of our trip and we'll be taking the ferry from Hong Kong harbour to Macau. The crossing takes about an hour, it will set us back HK$ 130/person and the boat leaves every half an hour until 19:30. This means we don't have to pre-book our tickets and can pitch up any time we chose; and it won't be too early either.
Now we just need our passport back (tomorrow) and that'll be that for the organising phase. *yay* back to doss mode.