Jade you can't defer the entire of the Reception year this way, just defer her start time in Reception. You can start her up to the term in which she turns 5. But she will still be starting in Reception. If you decided to wait the whole year she would be taken off roll and you would have to re apply as an in year application for year 1.
There has been a bit of a change about allowing August born babies to start Reception a year later but I don't know much about that. You would need to ask one of the experts here.