Yhe only thing I can suggest is creativity. Only one support staff member in class (who would obviously support others) and focus on independence, resilience znd asking for the right help at the right time. If you run extra curricular activities, this may cover lunch times. Do support staff run small group sessions before and after school> This is an additional option (depending on needs). If you have a key worker system these people could be first point of contact if the concern is and SEN one and make 6 weel;y or termly contact with home as appropriate.
Other sessions (out library/LRC does accelerated reader) could be added. Finally, if not afyer school sessions, do you run a homework session daily?
These would obviouslys be for all with the named provisions, and justifying this would be the social/emotional development. 1-1 at all times would seriously hampaer this – if you are secondary, the student will be adults when they leavee; I believe it would be damaging to development if they don’t learn socialisation and independece.
Of course, it future expectation is fully supported including how the student lives (not expected to live independently due to needs) then parents should be fighting for specialist placement – even if this is out of County.