Postponed VAT (T18) & C79

SUGGESTED

Hello,

We import goods from the EU & have been using a Freight Agent since January 2021. 

We operate under "Postponed VAT" and use the VAT code T18. All has been working OK but I have now discovered there are some errors where the Freight Agent has accidently by passed the postponed vat & these amount's of VAT will be deducted automatically from our deferment account.

I understand I can claim these back through the quarterly return once I have a copy of the HMRC C79 certificate. My question is how do I enter this into SAGE so it appears as a claim on the electronic quarterly VAT return?

Any help much appreciated.