Many site issues can be caused by corrupt cookies or cache. '''Warning ! ! ''' This will log you out of sites you're logged in to. You may also lose any settings for that website. * [https://support.mozilla.org/en-US/kb/delete-cookies-remove-info-websites-stored Delete cookies to remove the information websites have stored on your computer] {web link} * [https://support.mozilla.org/en-US/kb/how-clear-firefox-cache How to clear the Firefox cache] {web link} If there is still a problem, [https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode Start Firefox using Troubleshoot(Safe) Mode] {web link} A small dialog should appear. Click '''Start In Troubleshoot(Safe) Mode''' (not Refresh). Is the problem still there? While you are in Troubleshoot(Safe) mode; Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches. ''[https://support.mozilla.org/en-US/kb/forum-response-disable-hardware-acceleration How to disable Hardware Acceleration]'' {web link}

Many thanks, Fred. I did everything you suggested and it made no difference. So I then went on to Microsoft Edge and, on the same specific BBC page, got the same result. Conclusion: it's nothing to do with Firefox, it's the BBC! But thanks again!

Make sure you contact their support.