For the Love of Xs & Vs

Normal Sudoku rules apply. Place the digits 1-9 in each row, column and box without repetition. Anti-Knight: Cells that are a Knight's move apart (in chess) may not contain the same digit. Quadruples: Digits in a Quadruple circle must be placed at least once in the four cells touching that circle. XV: Digits separated by an X sum to 10. Digits separated by a V sum to 5. All Xs and Vs are given.