I'm glad to see you reaching out to us here in the Community, @paulbushby.
The banner will appear depending on the time your financial institution is ready to update in QuickBooks Online. It'll directly show from the Banking section as soon as it's supported for your bank account.
To identify if you can now upgrade, I suggest visiting the Understanding if you can upgrade your bank feeds to Open Banking article. It provide answers to frequently asked questions and the list of banks already supported for open banking.
Let me know if you have further questions or other concerns. Please know the Community has your back. I’ll be right here to assist further.
