There is currently no way to set or retrieve CIS fields via the api with the exception of:
- CIS Enabled (GET ONLY)
- CIS Value (GET ONLY)

This request is to be able to GET POST AND PUT all contact CIS fields via the API including:
- CIS Enabled
- Registered CIS Name
- CIS Rate
- Organisation Type
- Unique Taxpayer Reference
- Subcontractor Verification Number
- National Insurance Number
- Customer Registration Number

NOTE: Although Customer Registration Number is not under the CIS section, it IS mandatory if CIS Type is set to Limited Company so this needs to be included as part of this request.