It's a brand new installation and this is the first api I have installed, so no chance of another api conflicting.
I tried all I could think of but no other conflicts except the fb plugin.
I deleted the 1.3 version and re-installed my previous 1.1 version. I had to re-enter the FB details and hey presto it works.
It has even fixed the original problem and now allows me to enter via facebook and have editing priveleges in submit article and weblinks, which wouldn't work before.
Hard to understand, because it is all a fresh install, but seems like a real problem with 1.3 at least on this site.
Many thanks for your assistance.