Hi there, RogerSterling. I'm here to ensure you'll be able to correct VAT returns.
To assist you in correcting your VAT return, I highly recommend reaching out to HMRC. They can provide you with detailed steps for the action you need to take. With this, we can also make sure that you can send it successfully. For more information, please visit this link: https://quickbooks.intuit.com/uk/contact/.
You can open this article to see further details and a list of common VAT: VAT codes in QuickBooks Online: A complete guide.
Lastly, you may refer to this article to view various information on how to adjust the amounts on a return: VAT exceptions and reports in QuickBooks Online.
Let me know the result after following the details above. I'll be right here if you need further assistance with your VAT or any QuickBooks-related concern. Have a nice day!