Different schools have different admission policies. For community schools, as a rule, the local authority is the admissions authority. A lot of faith schools are their own admissions authority, although mostly they will still adhere to the same policy as the authority.
In 2011, the admissions process to reception is due to change.
This is to put in place the expectation that all children will start reception in September.
At the moment, some schools insist on this, some don't allow it, some are in between.
At the same time, schools will have to allow parents to start children in January or April if they want - and funding will be available for pvi places if you want your child to do this. (obv, this is under the current govt)
As posted, putting it back an entire year, would mean you start in Y1 - unless there is a specific SEN.
Speak to the school about it, once you have a place. There are other types of flexibility - short days are fairly common.