Thank you Collie, sc333, evandale and Jay2016
So it seems that it's not at also easy.
My reason wanting an extension is that my child would be starting her GCSE next year and I think it won't be wise to move over as that could affect her studies. Migrating now would take her out of her learning environment- school, friends, school mates, teachers and more importantly the educational system. It could very likely take her time to adjust to the new environment and educational system and it could have a detrimental effect on her performance. As you would all know secondary and higher secondary are critical periods in a child's education and the performance in those levels could determine the child's future.
Any suggestions ? Is the Australian secondary and higher secondary systems same as in UK or different ?