Just a note to say that Google Blogger went down for around 24 hours during which time I was unable to access my comments or even sign in. Blogger is now back up and running, but several comments have been lost. So, if you posted over the last few days your comment may have disappeared as a result of the maintenance that Google was performing. Sorry for any inconvenience and thank you for reading.
EDIT: May 23rd 2011. Missing comments have mysteriously re-appeared!