The scene where Georgia plays pool was written specifically for Jessica Raine when she revealed a deadly aim on the pool table. She potted every ball on every take.
According to the information shown on the missing persons database, Jacqueline Laverty is listed as being missing from June 2012. The file is given reviews every month and it's next review is November 2013 which would indicate that this episode takes place roughly a year and four months after the events of season 1.
Mark Bonnar (Dryden) & Allison McKenzie (Akers) also worked together on Shetland (2013) as Duncan Hunter & Gail Callahan respectively.
Gina McKee, who played Jacqueline Laverty in Series 1, made a brief appearance when DI Lindsey Denton was scrolling through the Missing Person database