Another thought is, she is doing this for your benefit. She's picked up that it's expected that she have such extreme difficulty, and she's performing as she believes is expected? Calling a nursery school every single day to update them of progress is kind of extreme - and your statements that you knew her fear was normal, etc., might have communicated to her that this is completely normal and expected behavior, if she has a preference of not going.
Have you ever communicated to her that she needs to stop this, and that you're getting impatient with her tantrums, and does she notice that no one else is behaving that way?
My youngest wouldn't go to nursery school two mornings a week when he was 2. So we waited til he was 3, and the first several weeks I'd tell him if he walked in there with a sweet expression on his face and didn't make a fuss when I left, there would be a fabulous reward on his carseat when I picked him up. It was a dollar store thing. The point was to instill the habit of walking in without clinging and crying. It was the habit of him learning to calm himself down, and the expectation that he learn to do that without being further coddled.
Best wishes.
"teacher" was supposed to be "teach her"
I agree with the others that her separation reaction is extreme and you need more professional help than a health visitor or parent liaison. You have really given this a true "honest go" of making her feel comfortable with her nursery school that sounds like it's loving, caring and consistent.
At this point there is either a family/relationship dynamic a therapist could spot and help you out with, or an extreme anxiety problem that may respond to meds or therapeutic strategies that teacher her to lower her arousal through biofeedback. My three boys had three different levels of separation anxiety (low, medium and high) and I think the strategies that you have used up to this point should have worked completely.
I wonder if getting her out of your parents house might actually help? Is there a relationship dynamic there that makes her possessive of you?
Thanks for your replies, she doesn't have any of those other problems.
I definitely agree with Annie, this - I think is something that might require professional help.
Does she also have any of the other problems listed below - which would signify it might be more then just anxiety?
nappropriate response to people: A child may avoid eye contact, resist being picked up or cuddled, and seem to tune out the world.
Inability or reduced ability to play cooperatively with other children or to make friends.
Inability to understand other people's feelings.
Need for a rigid, highly structured routine -- and being very distressed by changes in routines
Extreme hyperactivity or unusual passivity, and extreme resistance to change.
Aggressive, self-injurious behavior.
Repetitive body movements, including pacing, hand flicking, twisting, spinning, rocking, or hitting oneself.
Insensitivity to pain or lack of response to cold or heat.
Impulsive behavior and no real fear of dangers.
An unusual attachment to inanimate objects such as toys, strings, or spinning objects.
Frequent crying and tantrums for no apparent reason.
I'd talk to a family therapist. She needs some anxiety reduction strategies, and it doesn't sound like anything you can provide all by yourself.