Nice to have you joined this thread, @K-LM.

I want to make sure I provided you with the best fix to get around this issue. The original poster of the question did get this resolved. They were able to find the missing code. This was done with a screen share by our customer service team going through the steps that were listed in this thread.

Were you able to follow the troubleshooting steps outlined by my colleagues above? If not, I recommend going through them to get this resolved. 

If you have and the issue persists, I suggest getting in touch with our support team. This way, they can look into your account and investigate the cause of this. There, they can perform additional steps to assist you in fixing the issue. 

Once everything is in place, you can utilize this article for reference in filing your returns: File your VAT return and record tax payment in QuickBooks Online.

I'm all ears if you need more help with your VAT and QuickBooks Online (QBO), please let me know. Simply add the details in your reply and I'll get back to you as soon as possible. Keep safe and have a good one!