Thanks for your response Mal. You raised an issue here I had not even considered , i.e a quick trip into Hong Kong, since I have never been in Hong Kong this could be an exciting option.
It's pretty easy to fit into 5 hours. The traditional quick "tourist triangle" would be :
- Airport Express to Hong Kong station.
- Walk to bus, Bus to peak tram.
- Peak Tram to top of the peak.
- Explore.
- Bus back to Central (or peak tram back down ... but the bus down is better to give another view).
- check the time, if still plenty:
-- Catch star ferry across harbour.
-- Not sure you'll have much time left after that
--- if you do have plenty of time, have a wander around Tsim Sha Tsui (Nathan Road etc)
-- Hop back into ferry.
-- Hong Kong station back to airport.
There's some other threads about similar types of trips into Hong Kong, so perhaps worth a search.