Series One (All 22 episodes and about 3 hours of extras including 3 complete episodes with commentary by cast and writers, outtakes, and behind the scenes, and photo galeries) was released on Jan 8, 2002.

The version I have is Region 1 encoded.. and I don't know for sure if they are planning a Region 2 release, but now would be a good time to check Amazon.uk !!!

It goes for $119 US, but has been available online for as low as $70 US.

Good luck shopping for it!