Diane has a drunken one-night stand with Tony Hutchinson (Nick Pickard) and embarrassed upon her awakening, she secretly leaves his bedroom nonetheless Tony notices. Diane is stunned to discover her pregnancy after. Sinead gives birth to a baby girl, who she calls Katy O'Connor.
Diane and Tony enter a relationship during Diane's pregnancy and open up a family business together, along with Ste Hay (Kieron Richardson), called The Hutch. As Diane nears her due date, her and Tony visit Brighton. They then discover that they met when children there, before Diane goes into labor and gives birth to twins, whom the pair name Anthony and Dee Dee Hutchinson. They return to the village as a family, but their life is far from peaceful. Diane is shocked to discover that Sinead has turned to prostitution to keep herself afloat, and forces her to move in with her, Tony and Finn to avoid suffering financial difficulty. Unbeknownst to Diane, Finn rapes his teacher John Paul McQueen (James Sutton) after a long while of homophobic bullying, but Diane maintains the image that her son is well behaved. When Sinead enters in a relationship with Freddie Roscoe (Charlie Clapham), Sinead moves in with him and takes baby Katy with her. However, Katy falls ill and Sinead rushes her to the hospital, but nurse Lindsey Butterfield (Sophie Austin) insists there is nothing wrong with the baby and discharges her, believing she is trying to gain attention. Without Diane knowing, Sinead cuts her own finger and places her blood inside baby Katy's nappy to ensure she gets checked out properly, but Sinead later confesses this to Diane. Diane reveals the truth, and social services take away baby Katy and place her into care. Diane then fosters baby Katy to keep her granddaughter close, and warns Sinead to stay away. Diane and Tony then prepare to marry, but during the wedding, she is arrested for possession of drugs, which belong to Trevor Royle (Greg Wood).
Tony and Sinead have a secret affair, Diane finds out about this and leaves Tony. Diane and Tony are later offered the chance to work aboard in France, after they're forced to sell the Hutch to Marnie and James Nightingale. Following a heartbreaking farewell with Tegan Lomax, who passes up the opportunity to go to France with them Diane and Tony prepare to leave for France. However, Harry stops them asking for help, revealing that boyfriend Ste is back on drugs and that he can't deal with the fallout on his own. Tony stays behind to help Ste, whilst Diane leaves.