MelbournePaula
first of all you will need to have some idea where in London you need to live ie north/south, then you will have to narrow it down to the actual borough and then look at the schools.
Some areas are really popular for familys because they have good schools. If you choose to live in one of these areas you will have to do your research very well, as cathment area will become very important.
I live in a popular part of North London, schools do not have a set catchment area, it changes every year, based on the number of applicants they get. Basically if you find a school you would really like to go to, you need to live really close to it. Our local primary schools are all oversubscribed with catchment running at under half a mile, for them all, some are only 0.29 of a mile, so you really do need to live on the doorstep.
If you miss getting in at reception, (you apply the year before they start, I think in Oct/Nov, you find out about your school place in March and they then start reception in Sept) you then go on the waiting list held by the council (sometimes held by the school). The places are still given based on the same admission policy, its usually,
- statemented children/children looked after by the council 2. siblings 3. distance to school. This is different if you want a church school or school that sets their own admission policy.
Children do move in London so places do come up in the year, at our school we often have parents who move in to the area and manage to get one of their children in, but they may have to wait for a place to come up for their other children, so in these cases it is still important to live close to the school as even though you will be getting a place because of being a sibling, you will also be judged based on distance.
I hope this all makes sense to you, once you have an idea which borough you think you may need to be in, look on their website and look for the school admissions document. My local councils list on this, the furthest distance that children got into school from, for the past three years, this is reallly helpful.
Also be aware, that you can go to school in a different borough than the one you live in. I live on the edge of one borough but send my children to school in the neighbouring borough as the school is at the end of my road.
Finally, not all London boroughs are the same, they can have different admission policys and different timescales, so make sure that you do your research.
If you can live anywhere in London, I would start with the dreaded league tables and see which boroughs have lots of schools that do well, also if you think you will be here for a while don't forget to look at secondary schools, some boroughs have OK primary schools and dreadful secondary schools.
Good luck with your search, I hope this has been of help