nb. The only combinations not covered is where there are less than 17 overseas trained players.
Whilst with 17 overseas trained players the maximum number of Association trained players is 4, if there are 16 overseas trained players, we could have 5 association trained player, with 15 overseas players, 6 association trained etc - ie substitute one association trained player for an overseas trained player..
Key thing is a minimum of 4 Club trained within 8 Locally trained players to get a 25 man squad - but we could have any number of club trained players (up to 25 CT).