The photo of Tina Watts hugging a dog appearing in a dating app shown on Steve Arnott's smartphone is actually of the actor Martin Compston's real wife, actress Tianna Chanel Flynn, and their Staffordshire Terrier, named King.
In the two years since season 4 ended, Steve Arnott has healed from his injuries, is no longer in a wheelchair, and has grown a beard. He is still a D.S. while Kate Fleming has been promoted to D.I. (As well as, regained her family!)