Reasonable adjustments at work interviews

Hi,

I am a aspie.

I was recently asked asked to attend investigation interviews, two formal grievances had been written against me, based on meltdowns at work.

I knew questions would be tough, so I asked for reasonable adjustments to be made for support at meetings based that I might have a meltdown due to the type of questions.

I was told, it was my responsibility to provide those adjustments and not the company.

I was offered standard witness protection or a union representative. (I am not part of union, so irrelevant.)

Under Equality act I thought Autism was protected and employers had a duty.

Any thoughts would be kind.