I've been glossing over it tbh. If she says it I say "love you lots, you're my very favourite girl!" She seems to like that and although she still says it a lot she isn't anywhere near as upset as she was. Dh even managed to do her bedtime tonight without me having to do it!
I threatened to shut the door and say that she'll wake up her sibling. When she cries, I shut the door. Give it a few minutes and say, now do you want the door open? If so, you need to go to sleep! Still works now! Started it about that age. They're clever little things!
No advice I'm afraid but I'm watching with interest. We have a similar problem with DS who's the same age. If we don't stay on the room with him until he's asleep he gets really upset and we rub the risk of him waking his 4month old brother (who sleeps like a dream )
How long do you reassure for? I'd be tempted ro keep that really short so that she isn't getting loads of attention/stimulation. Others may well think this is a bit harsh, but at 2.5 I think a child can be told that mummy and daddy are just downstairs, remember that and take comfort from it and I'd be inclined to view sobbing etc. as having its roots in seeking attention/control.
But you know your own child and what you're comfortable with.