In 2005, Shaun was invited to write for the popular long-running Sunday evening ITV series by producer Archie Tait. His first episode, in Series 16, was One Small Step which went on to win a Royal Television Society Yorkshire Best Drama award in 2007. It was a unique episode - filmed entirely on the permanent sets, creating a claustrophobic atmosphere.
Shaun went on to write two episodes for Series 17 - Touch and Go and Danse Macabre (featuring Judy Parfitt). By Series 18 - the final series - he wrote no less than four episodes: England Expects (featuring George Cole), Cashing In, Strike Up The Band and My One And Only.
Determined to give PC Younger something of a love life, Shaun gave him a girlfriend and made him a wow on the dance floor.
He brought back "The Prof", played by George Cole, for an episode that referenced Whistle Down The Wind.
He broke Dawn's heart when her handsome young admirer proved to be shallow and selfish - and made Peggy an unexpectedly wise shoulder for Dawn to cry on.
In two episodes, he explored Bernie's admiration of Judy Garland, even bringing him face to face with his idol - or someone he thinks is his idol.
And it was Shaun who wrote the final scenes for PC Bellamy, when his time came to leave the series.