Hello, dinosglasgowltd.
When you cancel your QBO subscription, you'll receive an email notification to confirm the cancelation. It means there is no grace period once you cancel your subscription.
Also, once you cancel your QBO plan, you have read-only access to your company data for a year. To know more about it, please refer to this article: What happens to my QuickBooks Online data after I cancel?. It contains details about data availability and export policies after cancellation.
Additionally, may consider canceling your account after the VAT return to ensure your book is accurate.
In case you'd decide to resubscribe again in the future, you can easily reactivate your account. We'd love to have you back!
We hope you'll consider QuickBooks again in your future endeavors. You're still welcome to post here if you have any other concerns with your subscription or data. Stay safe!