Child arrangement order (maternal grandmother)

[nana&granda]

Hi,
I have received paperwork today to attend court as my grandsons maternal grandmother now wants contact with our grandson. I have already posted on a contact forum and received some very helpful advice regarding contact with parents. My husband and I have an SGO and our grandson lives with us. I am worried about going to court as we have absolutely no relationship at all with maternal grandmother, in fact she has verbally abused us in the street several times. We do not feel that she is stable enough to have contact. What can we do please? I would not consider supervising any contact and we have no one who could help with this. I am so worried that out grandson will be forced to have contact with a stranger as he doesn't know who she is, please help.