Aibu or whats my next step? N.Ireland based :-)

[youngmum2108]

My dd is currently moving into her last year of primary school (sitting her GL transfer test in November). She has a visual impairment which the school have been aware of from reception class! A new principal was appointed for September - so I met with her in September to discuss my dd needs and to make sure these were continued so she didn't struggle in class. Her teacher (following a few months of conflict with the new principal) went on the sick the last 8 weeks of school, meaning there were several substitute teachers in place the last 8 weeks of school.
I had a phone conversation with the principal to discuss my concerns regarding the unstable teaching structure now within the school and discovered that no information regarding my dds needs were passed on to the substitute teachers. I was informed by the principal that this "is not my responsibility" to pass on each childs needs. Whos responsibility is it?
I wrote a letter of compliant to the chair of BOG explaining my concerns. The response I got from him was promising but was not accommodating to set up a meeting to discuss. Once this was eventually set up (I gave a week when I was available anytime - email was responded to with a date and time with no request for confirmation so I hadn't replied as I had already stated my availability) both the principal and chair of BOG failed to attend. I have emailed the principal to request the formal compliant procedure but have got no response and no request to schedule a new meeting.
Aibu or what is my next step to ensure the welfare of my dd in the school is priority? (There are only 63 pupils in the school and three teachers) The principal is not very approachable and has an extremely defensive attitude when approached. I know of several parents that won't approach the school yard at all and a few letters of compliant have already been send to the school but not dealt with!