'Sinead Megan Marks-Chadwick is a fictional character from the British Channel 4 soap opera Hollyoaks, played by Stephanie Davis. The character made her first on-screen appearance on 1 September 2010. Sinead is played by Stephanie Davies
Sinead befriends Amber Sharpe (Lydia Lloyd-Henry) and her father Rob is promoted to headmaster when they knock Mr Forsyth unconscious during a prank. Sinead's stepmother Diane asks Sinead for help with injecting her IVF treatments and it begins to effect their relationship. Finn tells Sinead that he is worried Diane may forget about her step-children if she has a child of her own. Diane takes a pregancny test which confirms that her IVF was unsuccessful. Diane finds an abandoned baby at the hospital and takes him home. She tells Sinead she wants to keep him but is forced to ask Lynsey Nolan (Karen Hassan) for medical advice when he falls ill. Lynsey threatens to contact the authorities, but Anita tells Lynsey to back off. Initially unimpressed, Sinead later develops an attraction to Taylor Sharpe (Shaun Blackstock), despite distraction from Taylor's brother Arlo Davenport (Travis Yates) they begin dating. Sinead reads Amber's diary and she claims that Rob has fathered the baby she is carrying. Sinead and Diane later uncover Amber's baby paternity (Finn is the father) and she ends her relationship with Taylor. Rob's disgruntled ex-employeeEva Strong (Sheree Murphy) steals Amber's diary and Sinead convinces Rob to reinstate Eva in exchange for the diary. But Eva keeps pages and with the evidence, manages to imprison Rob. It is revealed after that Rob 's sexual relationship with Diane commenced as his pupil and Sinead's mother is still alive. Sinead and Ruby Button (Anna Shaffer) tease Esther Bloom (Jazmine Franks) after she pretends Sinead is her girlfriend.
Sinead is later attracted to Bart McQueen (Jonny Clarke) and he convinces her to contact her mother. She meets Morag (Lisa Coleman) who reveals that she walked out on her family because of stress. She reveals that Sinead had leukemia and Finn was a planned child to act as a bone marrow transplant. Sinead accepts Morag's offer to move to New York but she changes her mind when she realises Morag does not want to see Finn. Sinead becomes romantically involved with Bart and Diane disapproves as she believes that he will distract her from her education. Sinead travels Abersoch with her friends and is jealous of Bart's ex-girlfriend Maddie Morrison (Scarlett Bowman). Sinead, soon after, intoxicates herself and almost drowns in the sea. Upon hearing Sinead's near-death experience, she attempts to stop her her from seeing Bart. Tired of Diane's intervention, the pair prepare to flee Hollyoaks. Their new life starts by seeking residence, interviewing for employment at fairgrounds and caravan parks however they ultimately sleep on the streets. In need of fiances, Bart contacts Jason Costello (Victoria Atkin), his transgender ex-girlfriend, for assistance and Sinead is angered because of Bart's relationship with Jason before he identified himself as a transgender. Sinead's jealousy grows, leaving them to face an armed farmer, who owns the house they were stealing from. Sinead decides to save Bart and Jason despite learning that they have kissed momentarily. Sinead attacks Jason and mocks his transgender status. She returns to Hollyoaks and ends her relationship. Sinead starts sixth form college and originally upsets Maddie by kissing her boyfriend Toby (Alex Roe). Maddie pretends to be Sinead's friend and manipulates her. She realises that Sinead and Bart are growing close and convinces her to date Gaz Bennett (Joel Goonan) instead, which she later begins, Maddie encourages her to have sexual intercourse with Gaz and convinces Bart to plant stolen goods on Gaz, but Sinead is arrested. Maddie attempts to tell Sinead about Gaz's unexpected move on her, but Sinead refuses to believe her. While Gaz is about to dump Sinead, he and Sinead realise they have employment, selling concert merchandise in London, but only as a couple. At a Wretch 32 concert Bart invades the stage and sings a song for Sinead. This convince her to get back with him and Gaz leaves.
Bart is caught growing cannabis in his attic and he decides to runaway. Sinead tries to run away with him but he gets away with it. She soon becomes annoyed with him for smoking cannabis and tells him to stop or she will end their relationship. He goes to Amsterdam and tells Sinead he is leaving her, but he returns home and she forgives him. Sinead joins Maddie in a bullying campaign against Esther and they play a series of pranks and turn everyone against her. When Bart refuses to stop smoking cannabis she ends their relationship. She attends a party and secretly sleeps with a man and later reunited with Bart. Sinead joins her friends in a stolen van driving Ruby and Jono to their wedding. Bart and Esther chase the van to stop the wedding, but the vans breaks fail and they crash into a separate wedding venue. Jono (Dylan Llewellyn) saves Ruby but he, Maddie and Neil Cooper (Tosin Cole) die in the explosion. Sinead is told in hospital that she is pregnant. She steals a photograph of Rhys Ashworth (Andrew Moss) who also died in the crash, giving the impression he is the father of her baby. Shortly after the crash, Jono dies in Ruby's arms from a blood clot. Sinead and Bart decide to raise the baby together so, along with Ruby, pressure Esther in to keeping her and Bart's involvement in the crash a secret.
Sinead and Ruby's mistreatment of Esther escalates and worsens when Esther takes drastic action by attempting to commit suicide which leads her to require a liver transplant. Sinead and Ruby make a pact to agree that they hey had nothing to do with the bullying. However Ruby feels the pressure of guilt and confesses everything about her major involvement in the bullying to Esther's family. At the same time Sinead is asked by Diane about whether she was involved in the bullying. Sinead denies everything. Diane later searches Sinead's laptop and smashes it when she finds the many images Sinead has posted. Initially angry, Diane convinces Sinead to blame everything on Ruby, but this plan fails when Ruby reveals everything at a gathering. The morning after the event, headmaster Patrick Blake (Jeremy Sheffield) calls Sinead into his office. Sinead shows no remorse and is promptly expelled.