Hi
I have travelled on the singapore to manchester flight and the stopover in colombo was only about an hour while we picked up more passengers!!! are you sure its 6 hours?

Regarding drink, Fill your boots LOL Emirates are ok for alcohol and serve the drink during meal times and if you want more, then just ask the FA.

I cant remember now why i was in singapore for with emirates but i only flew into colombo on the return flight.

Plenty to do in Singapore airport, You can have a free tour of the city and also go and see a movie.

Long stopovers in dubai are OK if you are silver or gold but you might be able to get into town for the morning on your return

Malc