It could be you're opening an account from another region like the US. To purchase the QuickBooks Self-Employed (QBSE) product UK (United Kindom), you can go to this page: Self-Employed | Accounting Software.
There you can get the subscription by starting a free 1-month trial or get the 60% discount for six months.
But first, you may cancel the account to prevent duplicate charges before you can purchase the QBSE UK.
Here's how to cancel on a web browser:
Open QuickBooks Self-Employed.
Go to Settings ⚙ and select Billing Info.
Select Cancel now, then enter your feedback when prompted.
Select Cancel subscription.
Otherwise, the account subscription will cancel automatically at the end of the trial period without any fees if you're using a trial account. You can also contact our Care Support Team to help you cancel your subscription.