I much appreciate your responses, they have helped me solve the problem.
I don't know anything about Epiphany. I use Iceweasel, but instead of setting a default search engine, I set google as my home page.
That certainly is one solution, but I feel I should be in control of my search engine, whatever my home page.
you can open a tab, type in about:config and hit enter ...
Thanks for reminding me regarding about:config. You are absolutely right, google is the default and after some digging around I discovered VM had changed the DNS protocol earlier this year and this was causing problems. They did have an opt out link, (it did not seem to be working - the process is obscure), but after trying again it now seems to work.
Yes, I wondered whether I would need to upgrade to 2.30. But 2.22 is in the Debian repository, so if I apt-get won't I just get what I already have? I usually use synaptic from Gnome. If I do upgrade to 2.30 will I not lose my bookmarks and history?