This problem was solved by good advice from SAMBOLL – try version 2.5.
The moral of the story is don’t use Demon Internet to host WordPress because their platform uses down level software
AND
don’t use Demon Internet for anything else because there overall technical support is very, very poor.
I’ll be moving the site to the other ISP we use UK2 who are fare better on every count.
AND A VERY BIG THANKS TO SAMBOLL