Ebay has an unused Millbank bag - 6 hours to go though

http://cgi.ebay.com/British-Army-Issue-Millbank-Water-Filter-Bag-New-Unused_W0QQitemZ280369139765QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item41474d9035&_trksid=p4634.c0.m14.l1262&_trkparms=%7C293%3A1%7C294%3A30

Silvermans in the UK have them but they are pricey

http://www.silvermans.co.uk/AdvancedSearch/tabid/96/Default.aspx?Search=millbank