It's a mystery that has haunted Andrew Gosden's family for more than 18 years. On 14 September 2007, the then-14-year-old disappeared from his home in Doncaster. He was last spotted on CCTV leaving Kings Cross Station - and has never been seen since. It's something his loved ones are still trying to come to terms with. His father Kevin Gosden says that not knowing what happened to Andrew after travelling into London is almost impossible to deal with. "He walked out of the station, but someone,