I've no particular knowledge of this school, but there are certainly cases nationally that succeed on the basis of:
(a) medical/social need, and
(b) the extent to which the child would benefit from what is offered by the school
[in this instance the outreach work of the ASD unit you mention].
The greater the need, and the greater the potential benefit, then clearly the stronger the appeal case becomes.
There are a number of factors that can affect the outcome of an appeal, some of which are completely outside your control:http://www.elevenplusexams.co.uk/appeal ... school#c20