When data shows that a school has for example offered a places to children scoring X by July does that mean that offers can be made anywhere from 1 March until July? It's just that by July the lowest score offered to was X?

Yes. There is nearly always a bit of movement (or quite a lot, depending on the school) after national allocations day, but the most of it will be over by the end of the summer term.

_________________
Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read.Groucho Marx

Thank you ToadMum. So if a child didn't get their first choice or second etc on national allocation day they can ring the borough to see where they are in respect to waiting lists?

Yes - the Admissions details should tell you who actually holds the waiting list (in Southend, all the waiting lists are held by the LA until the end of the summer holidays - and beyond, for some schools - but in some areas I think the waiting lists are handed to own admission authority schools earlier than that). There may be a delay on when waiting list details are made available, as responses are processed, late applicants ranked, etc.

_________________
Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read.Groucho Marx