Thank you everyone. All your advice is very much appreciated.

I could personally cut ties with her in an instant but the kids love her and she does treat them well for the most part. It wouldn't be fair on them.

She was out for the most part today and I opened up the whole house and let all the air in, her negativity out. I am feeling a little more relaxed this evening.
I'm going to work on the visualisations and protecting myself until she finally leaves.