Lisalisa you have my sympathy.
Your mum sounds exactly like my grandmother-demanding,attention seeking,self obsessed,using ewmotional blackmail ect.It is uncanny but we have been through similar situations with her.
Samcj is right about the effect it has on your children though.My mum tried to keep the peace & always jumped when my gran asked her to & gran always made out that she was devoted to us,her grandchildren.But as we got older,we noticed how she treated our mum & she also began to use the same tricks on my sister & I,complaining that we didn't visit often enough,that we didn't care,that she was going to commit suicide because no one loved her.She refused to come to my wedding because I wouldn't arrange it her way & told everyone that we hadn't invited her.
Eventually,we found out about all the horrible things that she had inflicted on my mum & other family members & it did have a bad effect on my sister & I.Gran is dead now,thankfully.My sister refused to see her for the last 2.5 years of her life & although I did see her for DD's sake,I am still bitter about the years of misery she caused my mum & that she managed to put up a front of being the loving,caring granny,which a lot of people were taken in by.
Sorry,I am rambling,but I just wanted to let you know that it isn't your fault she is like this.Please get some distance between you so that she doesn't start doing the same thing to your children.
Re the Social services thing-I am sure that they would suss out your mum as soon as she phoned them.Would it be worth telling your mum that if SS get involved,they probably wouldn't allow her access to the children at all?