Just tried M11 before and after (final?) install and no such issues.
In M8 Konqueror starts with a blank page and thus no problems when type http://www.google.co.uk into url bar.
An infected SD card has been removed from the equation. indeed M11 was installed from it!
So, as suggested from the beginning that (very old) Mozilla page must contain exploits not envisaged at the time - but by what mechanism? If it is a highjacked DNS then that has rather more worrying implications beyond just M8.
The current router setup is as supplied by my isp TalkTalk (apart from passwords and WPA2 key). However, TalkTalk prides itself on taking a very parochial (nanny) position on security (for our own good!) and take control of the DNS servers by default
[Sorry about the loss of formatting but I couldn't find a way!. It looks OK in the editor!]DNS Information
Connection Name Primary DNS Secondary DNS
nas_0_38 18.104.22.168 22.214.171.124
nas_0_65 0.0.0.0 0.0.0.0
ttyUSB0 0.0.0.0 0.0.0.0
Not sure why there are three sets - only ever been one pair on previous routers.
Furthermore, I've discovered that they also take control of the firewall with all filters disabled locally....