I think you need to tell the school you will attend a meeting if they agree that it will proceed on the basis of your agenda, and send them an agenda listing your concerns with a final item for discussion about what they are going to do about it. You should go with an advocate - possibly a volunteer from the Dyslexia Association or an organisation like SOS SEN, or a paid advocate like Fiona Slomovic - who can take notes and can firmly keep them to the point. Afterwards the advocate should in effect write the minutes and an agreed action plan and send it to the school. That way, you may feel you have achieved something positive from the meeting and the school cannot say that you are not engaging with them. And from that point onwards you can firmly hold them to the action plan.
I work in a school and the expectation is that the class teacher must meet with every parent for parent's evening. If an appointment isn't made by the parent the teacher is expected to chase this up and get one made, even if it is at a different time/day. If a parent doesn't show then the teacher is expected to chase this up and make a new appointment. The HT expects this of the teacher, and for the teacher to do all necessary chasing. If it really is a no go then the HT will take over and chase further.