Moriarty - 5:50 pm on Mar 3, 2013 (gmt 0)
Thanks all, for your insights.
I have added the slash as you suggested, however it has not resolved my problem.
The .htaccess in my case is the one I quoted in my former comment - save that it is now updated to include your suggestion.
Has anyone any suggestions as to how to restore the permalink structure of my choice without /blog/. I have had this problem since my last upgrade.