The majority of SEN provision is statutory so it cant be cut in that way
I also believe, based on the service users I work with, that SEN families would have constituted a high number of Reform voters. Turkeys voting for xmas. The most vulnerable in society have voted for hard line, right wing (more right wing) policies because they think their own special cause is being overrun with other special causes and feel disgruntled.
Its like the vast majority of those voting for Brexit were people who relied on some way shape or form on the EU and its protections and income.