Hello iain67,
Although you have a connection to the internet, it appears like your PC is unable to access the iTunes Store. The resource below will provide some troubleshooting steps for this issue. I've highlighted some key information. Click on the link for complete details.
Resolve issues between iTunes and third-party security software - Apple Support
https://support.apple.com/en-us/HT201413
The following might happen if your security software is causing an issue with iTunes:
- Your iPhone, iPad, or iPod touch aren't recognized in iTunes, or they won't back up, restore, update, sync, or activate.
- You see iTunes Errors 4, 6, 1630–1641, 3000–3999, or 9000–9999.
- You can’t connect to iTunes Store to buy or download content.
- iTunes won’t open.
Before changing your security software's setup:
- Make sure that the date, time, and time zone are set correctly on your computer.
- Log in to an administrative user account, not a guest account.
- Make sure that you have the latest version of iTunes.
- Update OS X or Windows.
- Update your security software.
Regards.