My two are in the same room together. DS1 is 4 & DS2 is 2, 1 in a bed and one in a cot. A few months back it became a bit of a novelty to have DS2 in DS1's bed and they'd fall alseep together. DS1 would fall asleep almost imeadiately, DS2 would get borded and we'd go in a short time later and DS2 would be happy to hop into his. It never caused any issues so we were happy to do this. Everyone stayed where they were supposed to

There was a time when DS1 was waking before DS2 and hopping in his cot and waking him up. At first i didn't realise he was probably waking him up but eventually i did and i asked DS1 not to hop in DS2's cot and maybe just come into our bed, he did this and all was good.

Could what she's doing be a bit of attention seeking and prolonging bed time? Maybe within reason allow some kind of special night time routine where they can share their beds for a short time?? We read stories on DS1's bed and then we tuck in and i walk out. It works well for us. I think you've got to be able to give a little, make them feel like they are making some decisions for themselves and then they don't try and push the boundries so much.... Sometimes that works.....