Question: When was the British sitcom first broadcast on Channel 4 in which Margaret Alice Cabourn-Smith appears on?

Context paragraphs:
List of Black Books characters: Black Books is a BAFTA Award winning sitcom first broadcast on Channel 4 from 2000 to 2004.  It revolves around the lives of three main characters: Bernard Black, played by Dylan Moran; Manny Bianco, played by Bill Bailey; and Fran Katzenjammer, played by Tamsin Greig.  Bernard is the belligerent owner of the book shop Black Books, while Manny is his assistant, and Fran is their friend and neighbour.  All three characters appeared in all 18 episodes of the show.  Supporting characters appeared infrequently to support each episode's storyline, a number of whom were guest stars, as well as lesser known actors who went on to have major roles in British comedy series.  Co-writer Graham Linehan also appeared in Ep.  1.2 as the "I Love Books" customer and Ep 1.5 as a fast food customer.

Chickens (TV series): Chickens is a British sitcom that was first broadcast on Channel 4 as a television pilot on 2 September 2011, as part of the channel's "Comedy Showcase" season of comedy pilots.  It was then followed by a six-episode series that was commissioned on Sky 1 and broadcasting began on 22 August 2013 and ended on 26 September 2013.  The show is about three men who don’t go off to fight in the First World War and consequently become social outcasts in their village.  It was nominated for Best Comedy Programme at the 2014 Broadcast Awards.

Margaret Cabourn-Smith: Margaret Alice Cabourn-Smith (born July 25, 1975 in Richmond upon Thames) is an English comedy actress with appearances on "Catastrophe", "The IT Crowd", "Psychoville," "Peep Show" and "Fresh Meat".

Man Down (TV series): Man Down is a British sitcom first broadcast on 18 October 2013 on Channel 4 and starring Greg Davies as Dan, a man who hates his job as a teacher and who recently broke up with his girlfriend.

PhoneShop: PhoneShop is a British sitcom that was first broadcast on Channel 4 as a television pilot on 13 November 2009, as part of the channel's "Comedy Showcase" season of comedy pilots.  It was then followed by a six-episode series that was commissioned on E4 and broadcasting began on 7 October 2010.

Uncle (TV series): Uncle is a British sitcom written and directed by Oliver Refson & Lilah Vandenburgh.  A pilot episode was first broadcast on Channel 4 in December 2012, before the show was commissioned by BBC Three.  The first episode from the series, a remake of the pilot, aired on 13 January 2014.  "Uncle" stars Nick Helm, Daisy Haggard, Elliot Speller-Gillott and Sydney Rae White.  The show was renewed for a second series, and it began on BBC Three on 10 February 2015.

Lovesick (TV series): Lovesick (formerly known as Scrotal Recall) is a British sitcom created by Tom Edge which was first broadcast on Channel 4 in October 2014.  A second series was released on Netflix globally on 17 November 2016.  The show has been renewed for a third series.

Small Potatoes (1999 TV series): Small Potatoes is a British sitcom television series written by Richard Pinto and Sharat Sardana, first broadcast on Channel 4 from 1999 to 2001.  Starring Tommy Tiernan, Sanjeev Bhaskar, Morgan Jones and Omid Djalili, it is set in east London and follows the life of a video rental shop employee, Ed Hewitt, and his friends.

Porridge (TV series): Porridge is a British sitcom first broadcast on BBC One from 1974 to 1977, running for three series, two Christmas specials and a feature film also titled "Porridge" (released under the title "Doing Time" in the United States).  Written by Dick Clement and Ian La Frenais, it stars Ronnie Barker and Richard Beckinsale as two inmates at the fictional HMP Slade in Cumberland.  "Doing porridge" is British slang for serving a prison sentence, porridge once being the traditional breakfast in British prisons.

Catastrophe (2015 TV series): Catastrophe is a British sitcom first broadcast on 19 January 2015 on Channel 4.  It stars Sharon Horgan as Sharon Morris and Rob Delaney as Rob Norris, who get together after she becomes pregnant following a brief affair while he is in the UK on business.  Carrie Fisher, Ashley Jensen, and Mark Bonnar play supporting characters in the series.

Supporting paragraphs: Margaret Cabourn-Smith Catastrophe (2015 TV series)
Answer: 19 January 2015