we have a free school opened recently near us. A number of SN parents i know are viewing it as a serious option.
Low pupil no's, small class sizes, great structure, disclipline etc. A good option for those with mild/moderate needs who would benfiit from high level of pastoral care, free of LEA b*llocks
Actually they are clear that their aim is high academic standards i'm not sure if they realised just how much interst it would generate from those looking for good SEN provision
However it depends entirely on the "ethos" of the individual free school & which identified gap they are filling.
There are a number of groups looking to set up ASD specific schools under the free school banner.
Its no different to any school, free school or LEA controlled you must assess the school against the invidiual needs of the child.