I agree that only dollar sign is the available currency option in QuickBooks Solopreneur, and I'm here to provide you with more information about this, Southbourne.
Although one currency appears in Accounts and Settings > Advanced, the amount and currency symbol should automatically display as pounds before and after printing for UK-based Solopreneur accounts. Please see the sample screenshot.

Since what you've experienced is different, let’s troubleshoot by accessing your QuickBooks Solopreneur in a private window to see if any browser-related issues are affecting the functionality of your account. You can use these shortcut keys to access them:
- Safari: 11 or newer: ⌘+ Shift + N
- Chrome: Ctrl + Shift + N
- Firefox: Ctrl + Shift + P
- Safari: Command + Shift + N
After you can log in using a private browser, switch back to your regular browser and clear the cache. You can also use another supported browser as an alternative.
Additionally, you can check this linked article for help topics and ways to run reports: Reports QuickBooks Sole Trader.
Feel free to reach out if you have any additional questions or inquiries regarding printing concerns.