The requirements for home grown players to compete in Europe competitions and to compete in the premier league are different. Starting the year of 2010-2011 home grown rule will take affect for all 20 teams in the premier league
For the premier league
"As of (2010-2011) clubs will be required to have a squad named of up to 25 players, of which no more than 17 can be over the age of 21 and not home grown," Scudamore said.
"The definition of home grown is trained for three years under the age of 21 by somebody in the English and Welsh professional system.
"Clubs will have to declare their 25 at the end of August when the window shuts and then again at the end of January."
The rules do not specify what country players come from only that they trained 3 years in an English or Welsh academy while under the age of 21. It does not specify how many of these players must come from your academy and how many can come from academies in England/Wales. Also the number is not 6 it is 8.
Then to play in Europe you already need 8 home grown talents, as of the 08-09 season you needed 8 home grown players and 4 from the clubs own academy and 4 from academies from clubs in the same country that the club is from. Any team that is already in Europe already has players they need.
First link shows Premier League Rules, Second Shows Europe Competitions rules, and third explains why they went with this definition for home grown players.