Go to the Mozilla Add-ons Web Page {web Link} (There’s a lot of good stuff here) and search for a good ad blocker.

You should also use anti-virus protection programs on your system.

Thanks for the replies FredMcD, I am running anti-virus programmes on my system. Going to the Mozilla Add-on page didn't help me resolve this particular problem. I am already running an ad-blocker, but the "Fake Bluewin" page that comes through seems to bypass all of these hurdles, and replaces the page I am browsing with the scam/phishing page. What I couldn't find on the Mozilla pages was a way to block a specific website. It might be on there but I couldn't find it. Any other suggestions gratefully received.

You might want to try (Block Site by Ray) from the Extension Store I don't use it but it is there and it is recommenced by Mozilla. Also you might want to try going to preferences-Privacy & Security and clear all site data and see if that helps you also.

Once you have checck everything, open the Add-Ons Manager and make sure
what each one is and what it does.

I just found this: https://www.bing.com/search?q=Bluewin+malware

Thanks Tom J, I have first tried clearing the site data, and will see if that works. If not I will try your suggestion of an add on from the extension store.

And thanks again to FredMcD, I will also go through the add-ons as you suggest. Thanks too for the link, I will look through that thoroughly

The fake site has mercifully left me alone so far today, so I will come back to the forum in a day or two to report progress.

Cheers.