Complex sentence: The 1st series aired 6 episodes (10th November 2007-15th December 2007) showing on Saturday nights and the 2nd series will be premiereing on the 23rd January showing on Wednesday nights.
Split into simpler sentences: The 1st series previously aired on Saturday nights with 6 episodes (10th November 2007-15th December 2007). The 2nd series will be premiereing on the 23rd January and will now airing on Wednesday nights.