Thanks for getting back here in the Community, @andrew46.
When creating transactions with VAT, submitting a Tax Return isn't automatic. That being said, you can make a test run without sending them to HMRC.
Please check out the Submit a VAT return in QuickBooks article. It contains detailed instructions and screenshots on how you submit them through the system (scroll down to Submit a VAT Return to HMRC).
Also, I recommend exploring QuickBooks Online using our test drive. Please bookmark the following link for future reference: