One season wonders.

Jim Howick fine actor but it's noticeable how many shows he's been in that have only lasted one series. Wannabe could be next to add to The Aliens, Loaded and Babylon. Katy Wix the same with Together, Fried and Anna and Katy.

There's a good thread on it here: https://www.comedy.co.uk/forums/thread/33366/

Not a big fan of many of the ones you've listed but there are a lot of respectable ones that only ran for one series, yes