Section 19 Education Act 1996: What counts as 'suitable education' to be put in place if child cannot attend school? EHCP in place but not ...

... appropriate and under mediation/appeal, still naming school child cannot attend.
Professional reports available that state that education in school setting is not suitable and that specify suitable provision.
However, the LA have not arranged provision whilst child out of school as per s19 (for 2 years), and school (receiving high needs EHCP funding) are only arranging 1 formal lesson per week, and none of the other suitable provisions backed up by the professional reports.
Can this be viewed as insufficient provision (by LA and school), and/or as school failing the best endeavour duty?