Hi
I am in Sydney at present and spent a year in the UK when my daughter was ages 1-2, she is now 4. Your concerns are shared as I ponder the distress my daughter will no doubt experience leaving a pre-school where she is blissfully happy for a new school in a new country. There is a child in her class (4 teachers to about 22 children) that positively howls every single morning , on the other hand my daughter would cry if she couldn't go.
I can only guess at how frustrating this must be for you and your son. He may seem physically and intellectually a little ahead but possibly you have overestimated his emotional readiness for this type of a challenge. It is so hard to be the new kid! (at any age). He may be very scared but unable to verbalise his fears to you.
To me January is a long way off and in a child's life it is, but perhaps by then he will miss having "school" and be ready to embark on a new adventure in new country!
Something that comes to mind from my limited experience thus far is that the UK and Australia differ in their approach to starting school age.
My understanding is that in the UK children begin their formal education at the age of 4. I think the school year begins in September.
However here in Australia (NSW) that whilst a child may officially be entitled to begin primary school at the age of 5, it is the accepted practice to begin in the year they turn 6. The Australian school year is a calendar year, ie begining late Jan/early Feb..
The Sydney trend appears at odds with the UK in delaying for 2 years but I think acheives no worse result . Let me explain...although not compulsory children can attend pre-school ...at age 3-4 they do 2 days (9am-3pm) a week, and at age 4-5 they do 3 days a week. This prepares them quite well, many begin primary school with the basics, beginning to read and write. Sydney parents seem concerned about doing their children a dis-service(S) by sending a young 4- 5 year old into a class of bigger, much more advanced 6 year olds, hence the tendancy to wait until the year they turn 6. They then use that additional year to prepare by going to pre-school as described above, and also supplementing their skills through music, computer, sport, dance etc. When I first read about this it sounded a little kiasu to me!, but it makes sense if your child is born late in the year not to make them start school with children who may be almost 2 years older. By making sure your child will be among the eldest in the class it puts them at less risk of failure.This is compounded for boys by the current notion that it is wiser to start formal school later rather than earlier, in order to allow their social skills to catch up with their heights , and not set them up for a cycle of disruptive child/bad schooling experience.
I would suggest that you seek the counsel of some UK and australian primary school teachers as to their opinions. Your sons birthday may have a lot of bearing on what will be the best scenario in either country.
If you are coming to Sydney please be aware that it can be difficult to get a place at a local pre-school as it is the practice to register at birth...and at more than 1. This kiasu Sydney behaviour means that ultimately you may get in at the last moment into a pre-school of choice after the Kiasu mothers have had time to turn down the 5 surplus places their child has been given.
So my advice would be to make applications a priority and persevere as children do come and go all the time. There are also less traditional (eg steiner, montessori) pre schools and private pre-schools. You can get a full listing from the local council. The local community pre-school which my daughter attends has been great. It costs $30 a day...$600 a term (4 terms) but no meals provided. The school has a flexible arrangement so that the children can go into a slightly older group if it would be best.
So in order to find the best solution to your dilemma it might be necessary to start researching both the UK/Australian schooling systems now and work backward from there as to how to deal with the current dilemma.
all the best