This is a question full of hypotheticals. I know that absolutely nothing is predictable, but I am running through possible situations based on what's happening now. If that makes sense!
We may be moving away from our lovely primary school to spend a year overseas. We would then return to our same address & hope that we got a space there again... At the moment there are 5 people on the waiting list (2 in catchment) in my daughter's year. I know we would go to the top of the list because we live so close to the school.
if we were to be moving back now, there are two places in my daughter's year across the whole of the borough - one 2.5 miles away & one 4.6 miles away.
The council suggested that, because we would be looking for a Y3 place, we would be in a good position to win an appeal for in-year admission at our local school - I suppose that would force the class number up to 31 - because we could show there were personal & social reasons that she would benefit being there.
Does that sound possible to you? We will be going away anyway, but I want to have fully thought through the consequences of the move for our DD...