We would take DD1 to the loo before we went to bed for a few weeks, until she started to get grumpy with us getting her up. Once she started to get grumpy with us, we thought it better she stay in bed and not have to fight with her. Shes only had a couple of accidents since then. But I limit what she drinks after dinner, and I make sure she goes to the loo before bed. I also let her know that if she needed to go during the night than that was fine, she was allowed out of bed to go, and if she needed help then she could wake DH or myself up.
It rather cute to hear in the mornings her get up and go the loo before she comes and wakes us up.

Goodluck!!