Well I did that as above. Problem still exists. So will change my filter and if no better will have to ask about a new wifi router.
Funny though, that I had an issue with the notebook the next day at a campsite that had wifi, after doing the update.
Also as I uploaded the screen shot of my zones to the site you recommended, how do I remove it? I hadn't registered with the site when I uploaded it. Now when I click on the link I can't see anywhere to delete it. Will my security be compromised?
Thanks for all your help.