Sizes not visible on amazon variation listing

We have tried to sort this without any success and the beta system for help on Amazon just doesn’t give a contact option - it sends me in circles so I am hoping someone might be able to help.

We have a product with many child variations covering colour and size.

The customer page on amazon shows the items available in stock (which is fine) but when a customer clicks on a size - eg medium 2 it doesn’t give any information about the measurements for that size.

I wrote a paragraph explaining the sizing and how to measure and put this in “product description” on the parent product - but it doesn’t appear on any of the customer views.
I have tried adding info in the child section but that doesn’t work either.
There is a box when I try to edit parent to say that other sellers contribute and amazon will accept my changes if it feels they are useful but this is a product that no-one else makes or sells on amazon.
ANY idea about how I can find some way to show the sizing (I have thought of uploading a word doc in images showing the size chart but the amazon instructions say all images must show the product.
Any help much appreciated.
with thanks