I moved from Essex to Cheshire last year, and was living in rented in Essex. My landlord sold my house in Essex and gave me two months notice. I decided to move to Cheshire to be nearer to my boyfriend who lives in Cheshire. At the time I had a son in year 2 (top of the infants) and a son in year 8, (2nd year seniors) we had to move in the Easter holidays - ie part way through a school year. The way I did it was to find the schools that I wanted and then I spoke to both of them to find out the places situation. The primary school had places in year 2, but the senior school didnt have any places in yr 8 I then had to find out their catchment areas through the LEA and then looked up the houses in those places via rightmove.co.uk. I was lucky in that the LEA had a map on their website with big shaded areas of the catchment, so I could narrow it down. I sent off for prospectus from both schools and went round both of them. The house I had chosen I put a rental deposit down on. The school wouldnt hold a place until I had a tenancy agreement signed (or exchange of contracts document) so as soon as I had that, my youngest was given a place. Because the senior school had no places in year 8, I started the appeal process as soon as I had the tenancy agreement, and then went to the appeal board. You have to prove that your child getting a place will not prejudice the education of others, and that the impact on your child of not getting a place, would be greater than the impact of your child stretching the resources/facilities of the other children - see here
http://www.bbc.co.uk/dna/actionnetwork/A1182449 Dont forget that children may accept a place in a reception class and then not take it up (I work in a Reception class). Classes can go up to 30 generally, and people also move out of a school all the time.
Children move schools all the time, they move countries/towns/counties all the time - it does work - my children both got into schools within half a mile of our house - and I did it all on my own and relocated 250 miles as well :D