Which is best?

Night, if you can sleep on the plane.

But a flight from the UK to Oz is 24 hours so some of it is going to night/day anyway

Doesn't really matter you will experience both on your way here

I like day so I can look out of the window. However a lot of airlines make you shut the blinds and pretend it's night time even though it's light outside. I think so the cabin crew can have a break.

Our flight , London-Singapore-Perth was at 22.15. 12 hours to Singapore was fantastic because my DD slept most of the way. We kept her active for the 6 hours we were in Singapore then she slept for another couple of hours of the last flight I don't think for a minute she would of done this had we had a day flight.
However, we arrived in Perth 06.15 local time, so sleep patterns were all over the place & we suffered quite badly with jetlag for a week.
If you have kids & don't mind them being awake for the flight then imo arriving at destination on the evening would help you adjust to times/sleep paterns better.

Clear as mud?

Leigh

I try and work back from my arrival time. For example, if I am due in Sydney by bed time, I try and stay away for the whole flight, that way I know I'll sleep when I get there. Opposite if we are getting there during the day.

Can't say it helps with the jetlag though... still wide awake, full of beans at 3am.