Hi UKMaster,
This could be a result of too much data in your browser's cache. Let’s do the browser troubleshooting steps to see if this is the cause.
Please switch to a private browser and sign in to QBO. For Chrome, press Ctrl + Shift + N. For MS Edge and Firefox, press Ctrl + Shift + P. For Safari, press Command + Shift + N. This step disables the extensions and stops the cache from saving your browsing history.
If the correct tax code reflects this time, you can go back to your regular browser and clear its cache. If not, please try other browsers to see if this only happens to the one you are using.
If the issue persists, please contact our QBO Support Team. That way, they can start a screen-sharing session to check this further.
On the other hand, you can also check about reconciling an account in QBO and submitting VAT returns for your references in the future.
I am only here if you need more help with your transactions. I just wanted to make sure the tax codes show up correctly to avoid issues with your returns.