In their Procedures for Mid-Term (In-Year) Admissions document which is available as a PDF, it states, "Applications will be processed batches within a maximum of 10 working days". There are three appendices on the website too, one of which is Timetable for Mid-Terms 2013-14 (I presume there would have been a similar one for 2012-13), which is a spreadsheet showing three Process Periods. There are 15 working days which encapsulates the three process periods which do overlap. Process period 2 starts on day 5 of the first process period, process 3 starts on day 10 of process 1 and day 5 of period 2.
The process period is as follows:
Day 1 - open period
Days 2-4 input apps
Day 5 - close apps, DAT for FAP, snapshot applications
Day 6 - vacancies
Day 7 - input vacancies, allocate routine, snapshot applications
Day 8 - sibling checks, LA allocates, waiting list offer, update DAT
Day 9 - add late FAP check, allocation lists on SSE, run letters
Their mid-term/in year applications guidance notes state, "We allocate mid term applications in batches approximately every 2 weeks (although this will vary during the school holidays) on an equal preference".
It further states, "You may only appeal where you have applied and have been refused admission to a school. You will have 20 school days within which to state that you intend to appeal."
In the email from Admissions yesterday it stated, "Period 20 (2012/13) opened on 19.4.13, closed on 30.4.13 and offers were made on 9.5.13".
Your support and knowledge is, as ever, very gratefully received.