Ah ha Ann!! Another one that hasn't been advertised through Australia Post. Would you like me to send a newsletter to all the
Australia PictorMark (APM) subscribers, and put something on my blog for you?
I know Stampboards is a fantastic source of information, but some people are very, very focussed on just postmarks and rely on their news as I've outlined above. Entirely up to you ... I never do such a thing without permission.
And you're absolutely right about St Monica's of course! I'd forgotten it momentarily as I haven't finalised 2009 for the second edition of APM yet. A very nice postmark indeed but a little confusing as it obviously has a moveable date although from memory it was advertised as "commemorative" which usually means a single date or short date range only:

Do you have special covers available for sale on the day and if yes, how can we order them please, and how much do they cost? Presumably, the postmarker will also be available for the first day of use through the Windsor PO? Is the St Monica's one from 2009 still be used by Richmond? And will this new one for Windsor be an ongoing permanent for that location?
Whoever said a postmark is just a postmark didn't have a clue!
