are you going to regret this if you don't do it???
Internet is invaluable in researching the area, cheaper properties mean rougher areas.... look at smaller city living, Norwood Park is lovely, very boho. At least if you find a 6mnth rental you can get to know area, outer suburbs etc. Aussies are very animal friendly, you might just have to be squashed in until you find your feet.
Adelaide very cosmopolitan and you'll have no problem being recieved, everyone is friendly and almost everyone has a connection to UK so it opens conversations well. there is a website www.meetup.com/cities/au/adelaide that have lots different groups that arrange meet ups around the area based on your interests, this got reccommended to me.
regarding the plane, I travelled economy with 2 kids one 5 and one 2...was fine , you will be too. Book on-line in UK it was much cheaper, I flew with Singapore Airlines. Really reccommend!
Left UK with husband and family after having very few prospects left, Mr came out with job in September I followed beg Dec with kids. We'd visited 7 years ago, Mr's family live here, and we always wanted to come back. No regrets yet........!