My wife and I do this trip every year in either J or F. 2016 already booked thanks to GGL Joker!

Outbound it's difficult to stay awake LHR to SIN so I don't even try. SIN to SYD I try and nap initially and then stay awake as we then have another flight to TAS and a drive the other end. Take advantage of the QF lounge in SIN - the food is very good and it's nice just to unwind for a short while and have a shower if there is time.I tend to stick to peppermint tea on this sector and eat only lightly. Once in Oz we try and stay awake until about 8 or 9PM. It's tempting to grab a nap but it screws up your body clock. I have no trouble adjusting to Oz time but a different story on the return flight.

SYD to SIN I am usually awake and normally eat pre-flight in the QF lounge at SYD.

SIN to LHR is the worst part for me. I sometimes have to get to LHR, shower and then go to a meeting. In some ways this is the best way for me to deal with the jet lag.

This year I decided on the SIN to LHR to eat lightly, sleep and drink no alcohol. We arrived at LHR and I felt absolutely awful so in 2016 I intend to have a few drinks on this sector

You will be very tired when you get back to LHR. My plan for the most years is to shower and eat at LHR. Go home and go for a long walk and then a nap for an hour or two and then continue as normal. Expect 7-10 days (in my case) of feeling not quite 100% but it will pass and a trip to Oz is worth the price!