Our 3-year-old dd slept on her own in her own room until she was 2. Then we went away for a while and she started sleeping with us. She's been in our bed now for a year. She goes to sleep in her own bed, then sneaks into the big bed later. Most of the time we don't notice and we all get a good night's sleep. New baby coming in 6 months, and I know we have to sort this out in good time. What's the kindest way to end co-sleeping once and for all?