Cannot update any qtys in Sage50 using sData

SUGGESTED

Hi I'm currently using the sData adapter found in the Sage GitHub:
https://github.com/Sage/sdata-downloads

I also have a trial version of Sage v28.1.404.0

Ultimatley I would like to create an interface to maintain Product and Order information between Sage50 and another app but at the moment I'm just using Postman to make the calls to Sage.

Using Postman I have been able to create both Commodoties and Sales Quotes and view them in Sage, but no Quantity information ever gets updated, be that either the inStock of the commodity or the quantity in the salesQuotationLine. I shall put sample of both calls below. Any idea what I'm doing wrong?

--commodity

<entry xmlns:sdata="">schemas.sage.com/.../1" 
       xmlns:xsi="">www.w3.org/.../XMLSchema-instance"
       xmlns="">http://www.w3.org/2005/Atom"
       xmlns:crm="">schemas.sage.com/.../2008">
  <id/>
  <title/>
  <content/>
  <sdata:payload>
    <crm:commodity>
      <crm:reference>MyPROD3</crm:reference>
      <crm:name>Test Product 3</crm:name>
      <crm:inStock>500</crm:inStock>
    </crm:commodity>
  </sdata:payload>
</entry>

--quote

<entry xmlns:sdata="">schemas.sage.com/.../1" 
       xmlns:xsi="">www.w3.org/.../XMLSchema-instance"
       xmlns="">http://www.w3.org/2005/Atom"
       xmlns:crm="">schemas.sage.com/.../2008">
  <id/>
  <title/>
  <content/>
  <sdata:payload>
    <crm:salesQuotation>
        <crm:tradingAccount sdata:uuid="35b8f79c-c53d-4beb-810f-3bbea6089ce9" />
        <crm:type>Product Quotation</crm:type>
        <crm:salesQuotationLines>
            <crm:salesQuotationLine>
                <crm:commodity sdata:uuid="d7f6b335-2318-417e-8456-e3152ae9ea60" />
                <crm:quantity>14</crm:quantity>
            </crm:salesQuotationLine>
            <crm:salesQuotationLine>
                <crm:commodity sdata:uuid="46fe16e2-272c-4f9e-868c-82b132a34a0e" />
                <crm:quantity>18</crm:quantity>
            </crm:salesQuotationLine>
        </crm:salesQuotationLines>
        <crm:label>Sales Invoice Quotation</crm:label>
    </crm:salesQuotation>
  </sdata:payload>
</entry>