Who made this rocker?  

Why don't you ask them what documentation they have on it?  
Aage Christiansen for Erhardsen & Andersen would be an odd credit to pick randomly, which is to say that the perception that it is true wouldn't add much value to the piece to a low knowledge buyer (or to put it another way, they say Finn Juhl for Niels Vodder).  And the bit about it being "Model A" would be some imaginative story telling if they don't have an old catalog for it.  Or possibly it has a tag that says maker, designer, and model.
The one thing that is suspicious is that they called the company "Eras."  They company went by "ERAN"  Could just be a typo.
Or it could all be bogus.  But if they want to sell the chair with that story, they ought to be prepared to substantiate it.

Hi Leif.
You have a good point - I will try to write them 🙂
I can find a number of pictures via Google of the same chair, but none of these pages put a name on it and when I google Aage Christensen and rocker, this is the only hit. Also googling what else he made, it doesn't seem like his style.
ps. On a side note Leif, remember we talked about Rastad & Relling? I just got hold on a Bambi chair - lounge model 🙂

Hello,
I had the same rocker in my store few months. Unfortunately, i can'thelp you for the designer or manufacturer (despite much research, i've found nothing). But i can confirm it's Danish. Mine was marked " made in Denmark"...
If you find more information i'm curious to know them.... 

Thanks for the info, I'd be interested if anyone found anything else out. 
Regards Jon