Was a bit dubious when Merson was saying that, he was born in Basingstoke, hardly London.According to wikipedia he was initially at the Bradford academy before going to Man Utds, seems odd to call him a London lad.
His wife is from the South though so perhaps her career is the one driving any move to London although as @maccavennie says there have been people you'd think were closer to him who have reported he wants to stay in the area.