The SOAP POST response can't be altered and sinks to AVRO. The source tab in the second copy activity is blob, xml. The xml blob data is manually manipulated to remove the headers (data extracted from the AVRO blob)
It looks like this is a CDATA incompatibility:
https://learn.microsoft.com/en-us/answers/questions/76694/azure-data-factory-and-cdata-type-xml-incompatibil.html
One suggestion in the forum was to use Azure Logic Apps, another was that a data flow could cope with the issue.
Could you please advise the best way forward, thanks