Have been trying to get my 21 month old son to sleep in his bed, last few times we tried he went down fine, but a couple of minutes later came trotting down the hall very proud of himself! 2 nights ago, we tried shutting the door, it took him 10 minutes to work out how to open the door, so after several attempts he ended up in the cot again.
The next day we put one of the "Dreambaby" door handle covers on the inside handle of his door, we know he got out of bed, but when he couldn't get out he used his stool to get back into bed and went to sleep. Success at last! So a combination of door handle cover and stool (to enable access as the bed is quite high) solved our problem.
Last night with this success we tried our youngest in the same room for the first time. Both of them slept through.
I had been a little concerned how he would take the door being shut, but it's worked really well.