If 8 months is enough for you then so be it. I think moving back home is made harder by people referring to "failure". We haven't failed because we don't find Australia home and decide against staying for ever. If you moved cities within the UK, no one would ever say you'd failed - you just moved!
We hit the 3 year mark in November, then in a flood of tears on Boxing Day decided to move back home. We never had a huge urge to come here. I wasn't happy at work, neither was my husband, I suggested Aberdeen, he suggested Australia! I thought, what the hell, let's give it a go, if we don't like it we can always come back. It was fine at first, I really enjoyed work (job the same, just different environment) now it's just work. My husband (electrician) has been unemployed (and depressed and stressed) for most of the 3 years. This really has not helped. Took countless applications to get a job, temporary contract of course, then once work is done so is he. My husband always said he'd never go back to Scotand, which I think is why I always told myself, it'll get better soon. It didn't. If you've had enough after 8 months, don't spend time being miserable waiting for the day you decided to stay forever because it probably won't come. We're going to give it up to 18 months to save some money (although I'd go back tomorrow if I could), but I feel much happier now that the decision has been made!
Good luck with the move. If you are all happier back home, the rest will work itself out eventually. Any tips with movers would be appreciated!