Hi there How do I manually convert my account from US Dollars to GBP please?

I have all the instructions you need to use pounds as your currency, @sian.

Multi-currency is available in QuickBooks Online. Only one currency is supported in QuickBooks Self-Employed. To use the Great Britain Pound (GBP) currency, sign up for QuickBooks Self-Employed for United Kingdom users.

Here's how:

1. You can select your country through this link: https://quickbooks.intuit.com/choose-country/.
2. Hit on Plans and Pricing.
3. Under There’s a Plan whatever your business needs, click on Manage Self Assessment only.
4. Select Buy now & save.
5. Follow the rest of the on-screen instructions. 

If you choose to open a new account, make sure to cancel the previous one to avoid being charged twice. Let me show you how:

1. Sign in to QuickBooks Self-Employed in a web browser.
2. Select the Gear icon.
3. Click Billing Info and then Cancel subscription.

Moreover, feel free to use these articles for future reference on canceling your QuickBooks subscription: Cancel your QuickBooks Self-Employed subscription.

Keep me informed if you require further assistance with managing your account. I am available to help. Take care.