I'm in Sydney and went to visit in laws in Perth when ds was 5 months. We didn't change anything before leaving. We let him sleep when he needed to and he seemed to cope better than us with the transitions of time.

I live in Broome WA but we visit family I'm Melbourne a lot we have found that sticking to our 'home' time for their routine is a lot easier an save a lot of drama's when we get home! This may be different because your going backwards so if bubs bedtime was 7 you would be putting bub down at 4! Its all up to what you would prefer and how you would like your holiday to pan out :)

Sorry she's 14 months and in a good but not strict daytime routine, with bedtime the same each night