CREATE TABLE table_79825 ("Nat." TEXT, "Name" TEXT, "Since" TEXT, "Goals" FLOAT, "Transfer fee" TEXT)

What is the since year for the player with more than 3 goals and a transfer fee of 400k?
SELECT "Since" FROM table_79825 WHERE "Goals" > '3' AND "Transfer fee" = '£400k'
SELECT "Since" FROM "table_79825" WHERE "Goals" > '3' AND "Transfer fee" = '£400k'