Kass - I know exactly what you're going through. Izzy is doing the same as Bell at the moment and we're supposed to be going out next week, leaving her with my ILs. I'm stressing about it already. If it was my mum, I'd be ok because Iz is so happy with her, but she just doesn't see her other grandparents enough - their fault, not mine!! I think you can only give it a whirl leaving her, and just make sure that your mum knows that if she gets really distressed to give you a call so you at least have the option of coming home.