2.5 year old rocking back and forth

[Heckythump1]

My DD is 2.5 years old and i'm getting worried that she's not growing out of her rocking habit.
It started at about 9 months old when she would rock against the cot bars (sat up with legs out in front of her) to get herself to sleep. She would occasionally rock during the day - bashing (as she now calls it) against the sofa, either sat on the sofa or against the arm of the sofa sat on the floor.
The rocking in the cot got really bad around 18 months, she'd be up for hours in the middle of the night rocking and would be rocking so hard the cot would move across the room. We ended up moving her into a bed as we all needed to sleep! Rocking at night stopped pretty much straight away, but then massively increased during the day.
Now at 2.5, she barely sits still and rocks in the pushchair, at the dinner table, in the car seat, against the sofa, just sat in the middle of the floor when she's playing and if she's not rocking she's waving her legs around (when sat on a chair/in pushchair) she just can't sit still.
People at toddler groups are starting to give her funny looks (and it does look a bit weird to be honest) nothing seems to stop her, she just seems to go into her own little world when she's doing it.

Other than the rocking she's an amazing little girl, really bright, absolutely hilarious and has the most amazing speech and vocabularly.
She has always been delayed with physical milestones.... didn't sit until 8.5 months, didn't walk until 17 months and we also feel her walking/running is fairly immature for her age still now.

Any ideas what could be going on? We have her 2.5 year review with the Health Visitor next week, so will obviously be bringing it up then, but just thought I'd ask if any one has experienced anything similar and has any insight to what it could be?

It sounds like she is self soothing. This is also known as stimming for those on the autistic spectrum, it's a form of self regulation when over stimulated. I would definitely mention it to the health visitor.

It sounds like Rhythmic Movement Disorder. My daughter has it, she started at 6 months old and is still rocking at 6.

It's a sleep disorder but children can also rock/bang during the day, my daughter loves to rock back and forth in the car/bus.

We've had to pad her bed etc to protect her and she is under consultant care at a sleep clinic. She has it quite severely and it has a huge impact on her life (and mine). Feel feel to contact me.

I used to rock back and forth to music, found it soothing did it for years.
Even things like the hoover.
I'm not autistic, it became a habit I think! Found it relaxing. When I say years I mean from around 8 months to 12
My parents had no concerns just said they knew I would grow out of it!
But there wasn't as much awareness of things as there is now.