Next cheapest seems to be:
Store4DVD - £35.95
HMV - £39.99
This TV show is amazing... I've introduced quite a lot of friends to it who are also now hooked. This is why I was searching for this - find the best price for a friend who wanted to get the DVDs of the show after borrowing mine.
Hope this hasn't been posted before. Had a search and couldn't find it. Mods please remove if it has. My first deal post too, so here's hoping I can get the pic to work too!
Might be instore too but I don't know.