I think Notts struggle to get players to leave London, people who live there (especially young people)love it because its a multi cultural place with loads happening - I should know I can't get my daughters to leave there even though they now have families.
Sowunmi moved down the road from Bromley to Sutton probably with a good wage increase more than likely didn't have to move house or uproot the family.
There are a number of players playing in leagues lower than they are capable in the London Borough because they don't want to move ... especially North.