Holiday with the in-laws. Will I cope?

[hopey]

We are due to go on holiday with my partners parents on Tuesday and I am dreading it.
When we were asked by them if we would like to go, we jumped at the chance. Its our only chance of a holiday this year and we feel we need a break. The only problem is Mum-in-law. She is driving me mad already!! She has started to interfere in everything I do, never agrees with the way I do things and is constantly pushing me to change to her ways.
At the start I put up with it. They live in the north of England and us in the South, so its not as if we see them that often. But she's started ringing more and more often about the most stupid things and its really getting my back up!! The one thing she has started doing is going on about how she will have my baby girl for a month in the summer without me and my partner (as if I'd be without my girl for that long!) and when we go to visit her, she keeps saying to my baby that she's going to smuggle her away from us. I know you might think I'm being daft but I don't want her saying things like that to my child.
This holiday started off as a good idea, but now I'm just wondering how long it will take before I snap!!
I feel sorry for the woman as she doesn't get to see her granddaughter as often as she likes and I know she's jealous of my mum as she looks after my daughter while I'm at work, but I don't know how much more I can take.
Sorry for ranting on like a woman possessed, but I can't tell my partner and I really needed to get it off my chest.