Ben, have you taken your son on a long train or car trip before? Does he fidgit or get bored quickly? If so, take along a gameboy (and spare batteries) to keep him amused. Just remember to make him turn the volume off on the plane. Better yet, if he loves to read have a couple of books for him.
Going to Oz, you'll go through this cycle of events: 10pm-ish departure from LHR. You would of had to of been at the airport by 8pm and probably queued for an hour to check in. Dinner will probably be served within an hour to two hours of departure so you can hopefully gets some sleep. If you can try and limit it to 2 or 3 hour blocks. It's about 11 hours to Singapore.
After the meal there may be a snack run midway through the flight. Hopefully they will be patrolling with water ever so often as well. A light meal will be served before landing also.
On the ground at Singapore try and have a shower as recommended above at the Transit Lounge. You can also use the pool and gym for an additional fee. I used the treadmill when I had a 3 hour layover. Be quick if you can as I had to wait a while for a locker and shower. Try and get lots of walking in otherwise. Go upstairs to the open air deck for some fresh air (just avoid the smokers!)
On the 2nd leg to Melbourne, try and settle as soon as possible after the meal service. Earplugs and eyemask will help, as does some sort of sleep-aid. It's only a "short" flight of 7 to 8 hours, but as you will be woken up about 90 mins before landing for breakfast, you might only get 5 hours of sleep.
You arrive in the AM. Most people say stay up all day to avoid Jetlag. I've found I can stay up till about 2 or 3 and then I just have to sleep for a couple of hours. I find this better than staying up till 9pm and then waking at 3am! Even flying in J with the flat beds I found I couldn't avoid jetlag.
Going back is better. Watch all the movies Melb-Sing. You leave in the afternoon for a night arrival in Sing. Have another shower in Singapore and buy some duty free. The 13ish hour flight Sing-LHR is great for getting a good 8hrs sleep, plus the meal services either side.
Onboard, as above has recommended, bring a washbag to freshen up with. Toothbrush and paste for oral hygenie. Listerine strips are an easy way to carry mouthwash. Lip balm and face moisturiser to help your skin from drying out. If you suffer from sinus, then take Sinex spray to help unblock your ears. Happynose helps keep the nasal passages from drying out. Pack a few paracetamol as well for good measure. Nytol will help you sleep as will a good cotton eyeshade. Earplugs you can by at Superdrug.
If you find you get hot onboard and want to have a wash, try those new bodywipes by Sure and other companies for an almost freshly showered feeling!
Clothing should be loose, natural fibers and if possible, a change of clothes. Some people like to get into trackies, but if you are wearing them when checking in, you've got no hope of an upgrade!
Drink lots of fluids, preferbly just water.
Above all, relax, sit back, enjoy the flight, the game and your holiday!
[This message has been edited by dddc (edited 10-17-2003).]