When is series 3 of The Catherine Tate Show going to be available on region 1 DVD in the US?

I understand that it's available on Netflix here, but I can't seem to find any site (amazon.com, etc.) that is selling a region 1 DVD playable on US DVD players. Strange, considering both series 1 (2004) and series 2 (2005) are made readily available in this format. Series 3 aired in 2006. What's the hold up?