When to apply for secondary in London?

[camaleon]

I am now living in an area where we are very happy with our primary school, but there is nothing great re secondary.
My DD is in year 5, my DS in year 4. We are planning to move to the catchment area of Fortismere/Alexandra Palace (Muswell Hill). We are considering Latymer too since both kids if the kids are keen in taking the exam.
When shall we move? We live in rented accommodation and I don't mind changing location. However I want to delay it since we live around the corner of our primary school and we have a great neighbourhood with plenty of friends.
Where can I find the info?
Thanks in advance

For all state schools the application deadline is 31 October of year 6, so you'll need to be in your new place by then.

Thank you very much Titchy. This gives me some time, then.

Actually the Common Application Form deadline for state schools is 31 October, but the deadline to register for the Latymer and QE exams is in July of Year 5. Then the exams take place in Septermber of Year 6, so that you can get results and know whether you should bother listing the grammar schools before the 31 October deadline. I had the intention of moving into the Latymer catchment area but was told that I had to have moved at the end of Year 5. They are pretty strict about the catchment, as the school is oversubscribed, so check to make sure your new address is close enough.

Thanks Heron.
We are planning to move in Easter, so that should be fine. I guess this is the only good side of not having money to buy ever in London. I can move without much headache.