We would suggest that you look in the following places:
CPC Codes Part 4 of Tariff
Valuation Method Part 4 Tariff
Look up the Tariff Code
If available look up the Tariff code under CHIEF using DCOM
Items that have documents that may be required, will in some cases need to be declared as not required.
For example:
We tried a shipment of Sunflower Oil with one of our clients and they needed to declare that an Animal Heath Certificate was not required.

Document code: 9120
Reference: GBAHC (GB + Animal Heath Certificate)
Status: XX (not required ‘EX-Heading goods for which the document does not apply)