DH has 11 years teaching experience in a STEM subject in outstanding schools, and 4 years' at middle management. He now works in a 'top' private school in the South-East - accommodation is provided but 10% of wages are deducted for this. He is currently a Head of Department and we both suspect he is underpaid for his role but there is no transparency in the system. Could anyone suggest how much he should be on, roughly?