22 March 2011 2nd Large and 1st Large booklet stamps from 2011 MA11 printing on FDC with Born Free Horsham pictorial postmark.
The two booklets of 4 were available for the first time with no printers imprint. As this was a cover change Royal Mail made a specific date of issue, which coincided with the issue of the WWF special stamps. The postmark used is a pictorial one made for that issue.
SG U2970/1 (also used for other years).