Allow me to provide additional information on this, Nigel. I understand how important it is to access your files, let me route you to our contact support to help you reset your password.

Since QuickBooks Desktop (QBDT) is no longer supported in the UK, only our support team can access your account due to security reasons. You can follow the steps provided by my colleague above.

Additionally, you can check our article to learn how your books were moved from QBDT to QBO: Find out how your books will move from QuickBooks Desktop to QuickBooks Online

If you still have concerns about managing your password and migrating to QBO, don't hesitate to leave a comment. I'm always here to help.