I've got two daughters like that Mishap. I babysat whilst my daughter had a late teaching night last night, and after getting her nearly 4 year old twins in bed, with a half hour of stories, I went up 15 minutes later to find that one had emptied a trug of soft toys all over his sleeping brother who went off like a rocket - both stood at the safety gate crying 'want my mummy.'
After half an hour of reassuring and cuddles, the previously asleep one went back to sleep, then woke up again because of the racket his brother was making - both very tired and grumpy. Poor mum walked in after her 11 hour day and spent the next hour going through the whole bedtime routine again, with stories, cuddles, bathroom, tidying toys away. Then she phoned me to say everything was fine again, had a quick bite to eat and got in bed.
I don't remember being that calm when mine were that age, and I was still at home then, not holding down a full-time job. Like you say, great girls.
(I've put some more pics of twins Polly and Alice on my profile). Looking for more of my other grandchildren to download).