2yr old slipped back to bad habits

[Frizzuk1986]

Currently sat in the chair next to my 2yr olds cot (2 on Xmas eve) waiting for her to fall asleep.
She was a bad sleeper as a baby only napping for 30 mins to 1hr once or twice a day and would not sleep at night without someone with her.
At 10 months we had reached our limit and sleep trained but not to an extreme as I didn't ever want to leave her crying for long so instead we would let her cry a little and then go in and distract her from getting worked up (offer a drink, take her out on the landing in the light etc) and it seemed to work after a few months of it.
From about 1yr she has slept overnight very well (most of the time) and nursery managed to get her to consistently nap for 1.5-2hrs which she now continues at weekends.
However after Xmas at my parents where my mum would go in with her like a shot if she cried and then would sit with her while she went to sleep, she now won't sleep at home unless I sit with her.
If I leave the room and she notices she cries for me to "sit in the chair" and if I don't she screams and screams (she screamed for 15mins the other day as I was tied up with something else)
How can I get her out of this new habit?
Do I need to revert back to old techniques, is this what 2yr olds do?
I know she is a clever little madam so don't doubt that she is using her cries to manipulate me to come back to her room.

It's so frustrating when someone undoes your hard work in a short space of time.

If I was in your position I would go back to what worked previously. Hopefully because you've gone through it before she'll get the idea quicker this time around.

If I assume that you don't want to use distressing methods, then you need to show her she can trust you.

She will take longer to go to sleep and mess around if she thinks that you will sneak off when she settles. She'll therefore deliberately try to not settle so that you stay with her.

If instead she trust you. That you'll never sneak off until she is fully asleep, then she will go to sleep much more quickly. Once she trusts you to not leave her, you can start gradually withdrawing.

So you can move the chair a bit away from the cot. But stay there until asleep. Then turn the chair away from the cot, but stay there until asleep. Then move the chair to the doorway, but stay there until asleep. Then out of the doorway. Then start doing small 'jobs' while upstairs - tidy bathroom then go back to the chair to check. Then ditch the chair but stay busying yourself upstairs and keep poking a head round the door. Until eventually you can reach the point where you can put her down, leave the door open (until you go to bed) and leave her to go to sleep.

But its a gradual change and it starts by her trusting you to stay with her when she needs you.

I don't mind pushing her a bit as I know she is using her tears somewhat as she does her pout face before full tears but I also know she gets in a state and chokes herself up and I don't want that.
I was going to try staying with her and slowly moving towards the door but worry she will cotton on and then need a more direct approach.
Tonight I've struggled to even get her to lie down. It's been a real battle. She was just standing up holding the bars wanting more stories. I led her down and she screamed and got straight back up and the cycle continued. She got herself in such a state she snotted all over herself and the bed so new sheets were needed.
I'd hug her all night if I could but I need a break so I can function at work the next day and want to know that she doesn't rely on me as she had gotten into good habits.