Happily editing.  Went away for an hour or two and came back and now I can't toggle the little triangles which allow you to set effects parameters.   I have restarted the computer, tried different projects but no change.   

Strangely I can toggle some parameters but others don't respond to the mouse at all when I click.

Any solutions to suggest? (which preferably don't involve me starting a new profile...)

Thanks

Simon

OK.  Turns out I answered it myself.  Creating a new profile seems to be the actual solution due to a corrupt profile.

Maybe this might be useful to others...