DD did this too when she went into a big bed. After about a week of it, I'd been out one night and came home at half 9 to a house in pitch black - DH had had enough of her getting out, that he turned all the lights and tv off and just sat outside her door! We had to resort to this a few times, but then she did it on the night Greys was on so I missed most of it! anyway, i said we needed to find a better way - just by chance, one night, we did the books before the bath for some reason and then we sat at the table with DD, gave her a cup of milk and we had a coffee, when it came for bed, she went to sleep first time with no getting up and no house in darkness! Don't know whether it was the extra attention that she got just before bedtime that helped or what. Since DS came along, we don't tend to sit at the table as its his last feed time too, but she''l sit and have her milk and tehn have a special cuddle with DH and she still goes happily (most nights anyway!)